SAT Writing: Logical Comparisons and Idiomatic Expressions

Logical comparisons and idiomatic expressions are two grammar areas where even strong writers make errors - not because the rules are complex, but because incorrect forms sound natural in conversation and informal writing. The Digital SAT exploits this gap systematically: every comparison trap and every idiom distractor is a form that sounds acceptable in informal English but violates the formal academic English standard the test measures. Preparation for these question types is essentially preparation for formal academic language - the same standard that college writing instructors expect and that the test is designed to assess. “The population of Texas is larger than California” sounds fine in conversation. “Different than” appears everywhere in informal speech. The Digital SAT exploits this gap between what sounds acceptable and what formal academic English requires.

This guide covers both areas completely: the full logical comparison rule set with the “that of / those of” framework, the “like vs unlike” comparison trap, possessive comparison forms, and the 25 most commonly tested idiomatic preposition pairings - each with correct usage examples, wrong-form examples, and the specific traps the Digital SAT constructs around them.

For the complete grammar rules overview across all SEC categories, see the complete SAT grammar rules guide. For the comprehensive reference covering all rule categories in one place, see SAT Standard English Conventions: Complete Grammar and Usage Guide. For parallel structure and modifier placement, the companion concepts covered in the previous article, see SAT Writing: Parallel Structure and Modifier Placement. For timed practice, the free SAT Reading and Writing practice questions on ReportMedic provide Digital SAT-format grammar questions including comparison and idiom questions.

SAT Logical Comparisons and Idiomatic Expressions

Part One: Logical Comparisons

The Core Logical Comparison Rule

RULE: A comparison must compare like to like. Both sides of a comparison must belong to the same category of thing - you cannot compare a quantity to a place, a policy to a person, or a salary to a lawyer.

THIS RULE APPLIES TO: all comparison words and phrases including “than,” “as…as,” “like,” “unlike,” “similar to,” “different from,” and “compared to.”

THE TEST: Draw a mental equal sign between the two things being compared. If they can logically be placed on the same scale (salary vs salary, population vs population, method vs method), the comparison is valid. If they cannot (salary vs lawyer, population vs state, method vs researcher), the comparison is faulty and requires correction.

THE FIX: Use “that of” (singular) or “those of” (plural) to refer back to the comparable element, use possessive forms, or restructure the sentence so the main clause subject is in the same category as what follows “like/unlike/similar to.”

CHOOSING THE FIX: When two or more fix options are offered as answer choices, all are grammatically valid if they compare like to like. The Digital SAT will offer only one correct fix; evaluate each answer choice by applying the equal-sign test to confirm the fix makes the comparison logical.

Logical Comparison Pattern 1: Quantity vs Place

The most frequently tested comparison error: comparing a quantity or quality belonging to one place with the place itself rather than the corresponding quantity or quality of another place.

INCORRECT: “The population of Texas is larger than California.” LEFT SIDE: population of Texas (a quantity - millions of people). RIGHT SIDE: California (a state - a geographic/political entity). A quantity cannot be larger than a state. The comparison is logically invalid. CORRECT: “The population of Texas is larger than that of California.” “That” refers back to “population” → population of Texas compared to population of California. EQUAL SIGN TEST: “population of Texas = California” → fails. “population of Texas = that of California” (= population of California) → passes.
INCORRECT: “The GDP of China has grown faster than the United States.” LEFT SIDE: GDP of China (an economic metric, a dollar amount). RIGHT SIDE: the United States (a country). GDP cannot grow faster than a country. CORRECT: “The GDP of China has grown faster than that of the United States.” “That of the United States” = the GDP of the United States → GDP compared to GDP.
INCORRECT: “The average temperature in Phoenix is higher than Seattle.” LEFT SIDE: average temperature in Phoenix (a measurement). RIGHT SIDE: Seattle (a city). CORRECT: “The average temperature in Phoenix is higher than that in Seattle.” Note: “that in” rather than “that of” because the relationship between temperature and Seattle is locative (“in Seattle”) rather than possessive (“of Seattle”). Both can appear; “that in” is more precise here.
INCORRECT: “Housing costs in San Francisco exceed New York.” LEFT SIDE: housing costs in San Francisco. RIGHT SIDE: New York (a city). CORRECT: “Housing costs in San Francisco exceed those in New York.” “Those” = costs (plural) → costs compared to costs.

Logical Comparison Pattern 2: Salary, Price, or Rate vs Person or Entity

A common variant: comparing a salary, price, cost, or rate on one side to a person or institution rather than to the equivalent salary, price, cost, or rate of that person or institution.

INCORRECT: “The salary of a senior researcher is higher than a junior analyst.” LEFT SIDE: salary (a dollar amount - what a person earns). RIGHT SIDE: a junior analyst (a person). A salary cannot be higher than a person. CORRECT: “The salary of a senior researcher is higher than that of a junior analyst.” (“that of” refers back to “salary”) OR: “A senior researcher’s salary is higher than a junior analyst’s.” (possessive forms on both sides) Both corrections compare salary to salary.
INCORRECT: “The compensation package offered by this company exceeds our competitors.” LEFT SIDE: compensation package (benefits/salary). RIGHT SIDE: competitors (companies). CORRECT: “The compensation package offered by this company exceeds those of our competitors.” “Those” = packages (plural implied by “competitors”) → packages compared to packages.
POSSESSIVE ALTERNATIVE: Both “that of” and possessive forms are correct. CORRECT: “A senior researcher’s salary is higher than a junior analyst’s.” CORRECT: “A senior researcher’s salary is higher than that of a junior analyst.” Both compare salary to salary. The possessive form is equally valid and often more concise.

Logical Comparison Pattern 3: Method, Policy, or Approach vs Person, Company, or Institution

INCORRECT: “The research methods used in this study are more rigorous than the previous study.” LEFT SIDE: research methods (methodology - a set of procedures). RIGHT SIDE: the previous study (an entire study, not its methods). Methods cannot be more rigorous than a study. CORRECT: “The research methods used in this study are more rigorous than those used in the previous study.” (“those” = methods, plural → “those of” or “those [verb phrase]”) Note: “those used in the previous study” uses a participial phrase rather than “those of the previous study” to specify which methods of the previous study are being referred to.
INCORRECT: “Her approach to data analysis differs from most researchers in the field.” LEFT SIDE: her approach (a methodology - how she analyzes data). RIGHT SIDE: most researchers (people in the field). An approach cannot differ from researchers. CORRECT: “Her approach to data analysis differs from that of most researchers in the field.” (“that of most researchers” = the approaches of most researchers → approach compared to approach)
INCORRECT: “The company’s marketing strategy is more aggressive than its competitors.” LEFT SIDE: marketing strategy. RIGHT SIDE: competitors (companies). CORRECT: “The company’s marketing strategy is more aggressive than those of its competitors.” OR: “The company’s marketing strategy is more aggressive than its competitors’ strategies.”

Logical Comparison Pattern 4: The “Like” and “Unlike” Trap

“Like” and “unlike” introduce comparisons by nature. What follows “like” or “unlike” must be logically comparable to what follows in the main clause.

THE RULE FOR “LIKE”: “Like [X], [Y]…” requires X and Y to be the same category of thing. If X is a person, Y must refer to a person. If X is an organization, Y must refer to an organization.

DIAGNOSTIC: After reading a sentence that opens with “Like [noun phrase],” ask “what category is the noun in the Like phrase?” Then check whether the main clause subject is the same category. If not, the comparison is faulty and the main clause subject must be adjusted to match.

INCORRECT: “Like many successful companies, Apple’s product design is innovative.” ANALYSIS: “Like many successful companies” - the comparison introduces companies (organizations). Main clause subject: “Apple’s product design” - a design, not a company. Companies cannot be compared to product designs. CORRECT: “Like many successful companies, Apple prioritizes innovative product design.” “Apple” (a company) is now the main clause subject, directly comparable to “many successful companies.”
INCORRECT: “Unlike her predecessor, the new director’s policy emphasized inclusion.” “Unlike her predecessor” (a person - the predecessor is a person). Main clause subject: “the new director’s policy” (a policy - a thing, not a person). A person cannot be compared to a policy. CORRECT: “Unlike her predecessor, the new director emphasized inclusion in her policy.” “The new director” (a person) is now the subject, comparable to “her predecessor” (a person). POSSESSIVE TRAP: “the new director’s policy” - the possessive “the new director’s” makes the director appear to be the subject, but the grammatical subject is “policy.” The same possessive trap appears in “her research focused on…” - “her” is possessive, not the subject.
INCORRECT: “Like the research from 2015, the current study’s methodology was scrutinized.” “Like the research from 2015” (a study - the full research project). After the comma: “the current study’s methodology” (one component of a study). POSSESSIVE TRAP: “the current study’s methodology” - “the current study’s” is possessive; “methodology” is the subject. CORRECT: “Like the research from 2015, the current study faced methodological scrutiny.” “The current study” (a research project) now follows “Like the research from 2015” (also a research project). OR: “Like the methodology of the 2015 research, the current study’s methodology was scrutinized.” (methodology compared to methodology - also valid)
INCORRECT: “Unlike the results of other treatments, this medication showed no side effects.” “Unlike the results of other treatments” (results - outcomes of treatment). After the comma: “this medication” (a pharmaceutical product, not its results). CORRECT: “Unlike the results of other treatments, the results from this medication showed no side effects.” (results vs results) OR: “Unlike other treatments, this medication showed no side effects.” (medication vs treatments - categories match) CHOICE BETWEEN FIXES: both are valid. The second (“Unlike other treatments”) is more concise; the first (“Unlike the results of other treatments”) is more precise about what is being compared.

Logical Comparison Pattern 5: Plural “Those Of”

When the noun being compared is plural, “those of” (not “that of”) is required.

PLURAL: “The findings of this study are more reliable than those of previous studies.” “Findings” is plural → “those of” (not “that of”).
PLURAL: “The results obtained by this team surpassed those obtained by rival teams.”
SINGULAR: “The conclusion reached by this study differs from that reached by the 2018 meta-analysis.” “Conclusion” is singular → “that” (not “those”).
SINGULAR: “The approach taken by Dr. Park is more conservative than that of her colleagues.”

THE QUICK CHECK: Is the noun you are referring back to singular or plural? Singular → “that of.” Plural → “those of.”

Logical Comparison Pattern 6: Comparative Adjectives and Parallel Structure

Comparisons using comparative adjectives (“more X than,” “less X than,” “higher than,” “lower than”) must ensure both sides are in the same category.

INCORRECT: “The new model is more fuel-efficient than the old model was five years ago.” This is actually CORRECT. “More fuel-efficient than the old model was” - both sides describe fuel efficiency in context.
INCORRECT: “Writing this analysis requires more effort than to read the original paper.” LEFT SIDE: the effort required to write (implied gerund). RIGHT SIDE: infinitive phrase (“to read”). This is also a parallel structure error. CORRECT: “Writing this analysis requires more effort than reading the original paper.”
INCORRECT: “His conclusion was more convincing than any researcher in the study.” LEFT SIDE: his conclusion (a finding). RIGHT SIDE: any researcher (a person). CORRECT: “His conclusion was more convincing than that of any other researcher in the study.”

Eight Worked Examples: Logical Comparison in Context

The following complete sentences combine the comparison rules in exam-level complexity.

EXAMPLE 1: “The economic output of Germany is significantly larger than France.” ERROR: Economic output (a quantity) vs France (a country). CORRECT: “The economic output of Germany is significantly larger than that of France.” EQUAL SIGN TEST: “economic output of Germany = that of France” (= economic output of France) → passes.

EXAMPLE 2 (Similar to + possessive trap): “Similar to other leading research universities, Stanford’s endowment has grown substantially.” ANALYSIS: “Similar to other leading research universities” introduces a comparison requiring universities on both sides. Main clause subject: “Stanford’s endowment” (a financial figure, not a university). POSSESSIVE TRAP: “Stanford’s endowment” - “Stanford’s” is possessive; the subject is “endowment,” not “Stanford.” CORRECT: “Similar to other leading research universities, Stanford has seen its endowment grow substantially.” “Stanford” (a university) is now the subject, comparable to “other leading research universities.”

EXAMPLE 3 (Findings vs trial): “The findings of the new trial are more significant than the 2019 trial.” ERROR: “findings” (research outputs) vs “the 2019 trial” (an experimental study). Outputs cannot be compared to a study. CORRECT: “The findings of the new trial are more significant than those of the 2019 trial.” “Those of the 2019 trial” = the findings of the 2019 trial → findings compared to findings. “THOSE” because “findings” is plural.

EXAMPLE 4 (Salary vs person): “A neurosurgeon’s salary in Boston is higher than a general practitioner in rural areas.” ERROR: “salary” (a dollar amount) vs “a general practitioner” (a person). A salary cannot be higher than a person. CORRECT: “A neurosurgeon’s salary in Boston is higher than that of a general practitioner in rural areas.” (“that of” refers back to “salary”) OR: “A neurosurgeon’s salary in Boston is higher than a general practitioner’s in rural areas.” (possessive form compares salary to salary) BOTH are correct. The Digital SAT will typically offer only one of these fixes, and either is acceptable if offered.

EXAMPLE 5 (Unlike + different categories): “Unlike the company’s previous initiatives, the new program’s budget allocation was transparent.” ERROR: “Unlike the company’s previous initiatives” (initiatives - programs or projects) vs “the new program’s budget allocation” (an allocation - a financial decision). Initiatives and allocations are different categories. POSSESSIVE TRAP: “the new program’s budget allocation” - “the new program’s” is possessive; “allocation” is the subject. CORRECT: “Unlike the company’s previous initiatives, the new program was transparent in its budget allocation.” “The new program” (an initiative) now directly follows “Unlike the company’s previous initiatives” (also initiatives) → like compared to like.

EXAMPLE 6 (Immune response vs vaccines): “The immune response triggered by this vaccine is stronger than other available vaccines.” ERROR: “immune response” (a biological reaction - antibodies, T-cells, etc.) vs “other available vaccines” (pharmaceutical products). A biological response cannot be compared to a product. CORRECT: “The immune response triggered by this vaccine is stronger than that triggered by other available vaccines.” “That triggered by other available vaccines” = the immune response triggered by other vaccines → response compared to response. Note the participial phrase “triggered by…” is maintained on both sides, ensuring structural parallelism within the comparison as well.

EXAMPLE 7 (Infrastructure vs countries): “The infrastructure in developing nations is often less developed than wealthy countries.” ERROR: “infrastructure” (physical systems - roads, power grids, telecommunications) vs “wealthy countries” (nations). Infrastructure cannot be compared to countries. CORRECT: “The infrastructure in developing nations is often less developed than that of wealthy countries.” “That of wealthy countries” = the infrastructure of wealthy countries → infrastructure compared to infrastructure. SINGULAR “THAT”: “infrastructure” is singular (even though it comprises many systems) → “that of” rather than “those of.”

EXAMPLE 8 (Style vs writers): “Her novel’s prose style is more accessible than most contemporary literary fiction writers.” ERROR: “prose style” (a writing quality) vs “most contemporary literary fiction writers” (people). A style cannot be more accessible than writers. CORRECT: “Her novel’s prose style is more accessible than that of most contemporary literary fiction writers.” “That of most contemporary literary fiction writers” = the prose style of most contemporary literary fiction writers → style compared to style. OR RESTRUCTURE: “Her prose style is more accessible than that of most contemporary literary fiction writers.” (Removing “novel’s” from the subject makes the subject “she/her” implicitly, but the possessive “her prose style” still works.)

Part Two: Idiomatic Expressions

Why Idioms Are Tested on the Digital SAT

An idiomatic expression is a phrase whose correct form is determined by convention rather than logical rules. “Different from” is correct not because any rule prohibits “different than” but because formal academic English has established “from” as the conventional preposition after “different.” The Digital SAT tests whether students know the conventional pairings - the specific prepositions, particles, or constructions that combine correctly with particular adjectives, verbs, and nouns.

WHAT THE SAT TESTS: The test focuses on preposition pairings (adjective + preposition, verb + preposition, noun + preposition) and on a small number of specific phrase constructions. The wrong answers typically substitute a plausible-sounding but incorrect preposition.

HOW TO SPOT IDIOM QUESTIONS: idiom questions often present four answer choices that are identical in every way except for the preposition after a key verb or adjective. When the only variation among the four choices is the preposition, the question is testing the idiom rule. This recognition - “all four choices have the same structure except for the preposition” - is the visual cue that triggers the idiom recall check.

The 25 Most Tested SAT Idioms

The following 25 idiom pairings are the most frequently tested on the Digital SAT. Each includes the correct form, the wrong form most often presented as a distractor, and an example sentence.

Group 1: Adjective + Preposition Pairings

DIFFERENT FROM (not “different than”) CORRECT: “Her approach is different from her predecessor’s.” INCORRECT: “Her approach is different than her predecessor’s.” RULE: “Different from” is standard in formal American English for comparisons between nouns and noun phrases. NOTE: “Different than” appears in informal speech and before a clause (“Her results were different than we expected”), but “different from” is the required form on the Digital SAT whenever “different” precedes a noun or noun phrase. MEMORY AID: “Different” implies separation or departure - you move AWAY FROM something different, not TOWARD it. “From” captures this directional meaning.
SIMILAR TO (not “similar with” or “similar as”) CORRECT: “The new method is similar to the established protocol.” CORRECT: “Her results are similar to those found in the earlier study.” INCORRECT: “The new method is similar with the established protocol.” (“with” implies association, not similarity) MEMORY AID: “Similar to” parallels “identical to” and “comparable to” - all three use “to” when expressing likeness or equivalence.
IDENTICAL TO (not “identical with” or “identical as”) CORRECT: “The second sample was identical to the first.” CORRECT: “The results were nearly identical to those reported in the 2019 study.” INCORRECT: “The second sample was identical as the first.” (“as” does not pair with “identical”) MEMORY AID: Think of identity as pointing TO something - “identical to X” means “the same as X,” and the “to” points toward the thing being matched.
RESPONSIBLE FOR (not “responsible of” or “responsible to do”) CORRECT: “The committee is responsible for approving budgets.” CORRECT: “Each researcher is responsible for the accuracy of their own data.” INCORRECT: “The committee is responsible of approving budgets.” (“of” is not idiomatic with “responsible”) MEMORY AID: Responsibility is held FOR something - you have accountability FOR the outcome. “For” captures this accountability relationship.
CAPABLE OF (not “capable to”) CORRECT: “The system is capable of processing data in real time.” CORRECT: “Only a few institutions are capable of conducting research at this scale.” INCORRECT: “The system is capable to process data in real time.” (“to” + infinitive doesn’t follow “capable” - “capable” requires “of” + gerund) MEMORY AID: Capability is a possession OF a quality or ability. “Capable of [gerund]” = possessing the ability to perform that action. “Of” signals possession.
INTERESTED IN (not “interested to” or “interested about”) CORRECT: “She is interested in pursuing graduate studies.” CORRECT: “The committee expressed interest in funding further research.” (noun “interest” also takes “in”) INCORRECT: “She is interested to pursue graduate studies.” (acceptable only before specific verbs like “learn,” “discover,” “note”) NOTE: The construction “interested to [verb]” is acceptable in very specific contexts: “I was interested to learn that…” where the verb describes reception of information. For all other contexts (especially before a noun or gerund), “interested in” is the standard form.
FAMILIAR WITH (not “familiar of” or “familiar to”) CORRECT: “The researcher is familiar with the existing literature.” CORRECT: “Students entering the program should already be familiar with basic statistical methods.” INCORRECT: “The researcher is familiar of the existing literature.” (“of” is not idiomatic with “familiar”) NOTE: “Familiar to” has a different meaning - something is “familiar to” someone when they recognize it: “This pattern is familiar to researchers in the field.” The test uses context to determine whether “familiar with” (person knows something) or “familiar to” (something is recognizable to person) is needed.
INDEPENDENT OF (not “independent from”) CORRECT: “The results were independent of the researcher’s hypothesis.” CORRECT: “Each panel operates independently of the others to prevent bias.” INCORRECT: “The results were independent from the researcher’s hypothesis.” (informal but not formal standard) NOTE: “Independent from” appears in informal usage (“She became independent from her parents”) with a slightly different meaning (freedom or separation from an entity). In academic usage for research contexts, “independent of” is consistently the correct form.

Group 2: Verb + Preposition Pairings

REGARD AS (not “regard to be” or “regard like”) CORRECT: “Experts regard this discovery as significant.” CORRECT: “Experts regard this as the most important discovery of the decade.” (“regard [noun] as [noun]”) INCORRECT: “Experts regard this discovery to be significant.” (“to be” is never used with “regard”) INCORRECT: “Experts regard this discovery like a breakthrough.” (“like” introduces comparisons, not classifications) MEMORY AID: “Regard as” is equivalent to “classify as” or “identify as” - all three use “as” to signal the categorization or assessment.
PROHIBIT FROM (not “prohibit to”) CORRECT: “The policy prohibits members from voting on their own contracts.” CORRECT: “Photography is prohibited from occurring in restricted areas.” (passive) INCORRECT: “The policy prohibits members to vote on their own contracts.” (“to vote” would require “allows” or “permits,” not “prohibits”) MEMORY AID: “Prohibit” means “prevent from.” The “from” is built into the meaning of the word. You prohibit someone FROM doing something - they are kept FROM the action.
SUCCEED IN (not “succeed at” or “succeed to”) CORRECT: “The team succeeded in replicating the results.” CORRECT: “She succeeded in completing the project ahead of schedule.” INCORRECT: “The team succeeded at replicating the results.” (informal, not formal standard) INCORRECT: “The team succeeded to replicate the results.” (“succeed to” is not idiomatic in this sense) MEMORY AID: Success happens IN a domain or IN an activity. You succeed IN something - you operate within the field and achieve results within it.
COMPLY WITH (not “comply to” or “comply by”) CORRECT: “All participants must comply with the protocols.” CORRECT: “The organization has fully complied with all regulatory requirements.” INCORRECT: “All participants must comply to the protocols.” (“comply to” is not idiomatic) INCORRECT: “All participants must comply by the protocols.” (“comply by” is not standard) MEMORY AID: Compliance is conformity WITH a standard. You align yourself WITH the rules - “with” captures the alignment relationship.
ATTRIBUTE TO (not “attribute with” or “attribute for”) CORRECT: “The researchers attributed the improvement to the new intervention.” CORRECT: “Scholars attribute this work to an anonymous medieval scribe.” (assign authorship) INCORRECT: “The researchers attributed the improvement with the new intervention.” (“attributed with” is wrong) INCORRECT: “The researchers attributed the improvement for the new intervention.” (“for” is wrong) MEMORY AID: To attribute something is to point TO a cause or source. The attribution goes in the direction of the cause - hence “to.”
DISTINGUISH FROM (not “distinguish than” or “distinguish against”) CORRECT: “It is difficult to distinguish correlation from causation.” CORRECT: “The study sought to distinguish genuine effects from statistical noise.” INCORRECT: “It is difficult to distinguish correlation than causation.” (“than” is for comparisons, not distinctions) MEMORY AID: To distinguish X from Y is to separate X FROM Y - you pull them apart, moving one AWAY FROM the other. “From” captures this separation.
RESULT IN (not “result to” or “result into”) CORRECT: “The intervention resulted in measurable improvement.” CORRECT: “Years of preparation resulted in a successful launch.” INCORRECT: “The intervention resulted into measurable improvement.” (“into” implies transformation, not outcome) INCORRECT: “The intervention resulted to measurable improvement.” (“to” is not idiomatic here) MEMORY AID: A result exists IN a domain - the outcome materializes within a space (“in improvement,” “in success,” “in failure”). Think of the outcome as something you arrive IN, not something you arrive TO.
STEM FROM (not “stem in” or “stem because of”) CORRECT: “The problem stems from inadequate funding.” CORRECT: “Many of the errors in the dataset stem from inconsistent data entry procedures.” INCORRECT: “The problem stems in inadequate funding.” (“in” is not idiomatic with “stem”) MEMORY AID: A stem grows FROM its root. Problems “stem from” their causes - they grow outward FROM the source. The source is what you move FROM.
ACCOUNT FOR (not “account to” or “account about”) CORRECT: “Researchers must account for all confounding variables.” CORRECT: “The model failed to account for the role of socioeconomic factors.” INCORRECT: “Researchers must account about all confounding variables.” (“about” is not idiomatic with “account”) MEMORY AID: To account FOR something is to take responsibility FOR it or make provision FOR it - “for” signals that the thing after it is what is being covered or addressed.

Group 3: Noun + Preposition Pairings

DEBATE OVER / DEBATE ABOUT (not “debate on”) CORRECT: “The debate over climate policy has intensified.” CORRECT: “There is ongoing debate about the methodology among scholars.” LESS PREFERRED: “The debate on climate policy has intensified.” (common but not formal standard) NOTE: “Debate over” and “debate about” are both correct and preferred. “Debate on” is common in informal usage but the Digital SAT’s formal passages favor “over” or “about.” MEMORY AID: A debate goes OVER a contested issue (it circulates around, covering the question from multiple angles) or is ABOUT a topic.
BAN ON (not “ban against” or “ban of”) CORRECT: “The committee imposed a ban on single-use plastics.” CORRECT: “The international treaty includes a ban on chemical weapons testing.” INCORRECT: “The committee imposed a ban against single-use plastics.” (“against” is not the standard pairing with “ban”) INCORRECT: “The committee imposed a ban of single-use plastics.” (“of” is wrong) MEMORY AID: A ban is placed ON a category of things - it sits ON top of them, applying to them. “The ban on X” means the prohibition applies specifically ON or TO X.
CONCERN ABOUT / CONCERN OVER (not “concern of”) CORRECT: “There is growing concern about data privacy in the research community.” CORRECT: “Concern over the findings led to a second independent review.” INCORRECT: “There is growing concern of data privacy.” (“of” is not idiomatic with “concern”) NOTE: Both “concern about” and “concern over” are standard. “Concern of” is always wrong. MEMORY AID: You are concerned ABOUT something that troubles you - your attention is directed TOWARD the concern. “About” and “over” both capture this directed attention.
INTEREST IN (not “interest for” or “interest about”) CORRECT: “Her interest in neuroscience led to her doctoral research.” CORRECT: “The growing interest in renewable energy has attracted significant investment.” INCORRECT: “Her interest for neuroscience led to her doctoral research.” (“for” is not idiomatic with “interest” as a noun) NOTE: “Interested in” (adjective) and “interest in” (noun) both use “in.” MEMORY AID: Interest is located IN a domain. You have interest IN a field - your attention is directed WITHIN that area.

Group 4: Phrase Constructions

SO…THAT (not “so…as to” or “so…which”) CORRECT: “The sample was so small that the results were inconclusive.” CORRECT: “The findings were so surprising that the team immediately launched a follow-up study.” INCORRECT: “The sample was so small as to make the results inconclusive.” (less preferred) INCORRECT: “The sample was so small which made the results inconclusive.” (“which” cannot replace “that” here) NOTE: The Digital SAT tests “so [adjective] that [clause]” as the standard consequence construction.
AS…AS (not “as…than” or “as…like”) CORRECT: “The new model is as accurate as the original.” CORRECT: “The results are not as conclusive as the team had hoped.” INCORRECT: “The new model is as accurate than the original.” (“more…than” and “as…as” are two separate constructions that must not be mixed) MEMORY AID: “As…as” = same degree. “More…than” = greater degree. Never mix the two patterns.
NOT SO MUCH…AS (not “not so much…but” or “not so much…than”) CORRECT: “The challenge is not so much the data collection as the interpretation of the results.” CORRECT: “The problem is not so much what the data shows as how it has been framed.” INCORRECT: “The challenge is not so much the data collection but the interpretation.” (“but” cannot replace “as” in this construction) INCORRECT: “The challenge is not so much the data collection than the interpretation.” (“than” is for comparisons with “more/less,” not with “not so much”) MEMORY AID: “Not so much X AS Y” - the “as” introduces the more accurate or greater element. Y is what it IS more than X. The construction uses “as” for contrast, not “but” or “than.”
MORE…THAN / LESS…THAN (not “more…as” or “less…as”) CORRECT: “The second phase was more complex than anticipated.” CORRECT: “The revised protocol is less time-consuming than the original.” INCORRECT: “The second phase was more complex as anticipated.” (“as” belongs to “as…as,” not to “more…than”) INCORRECT: “The revised protocol is less time-consuming as the original.” (“less…as” is not standard) MEMORY AID: The two degree constructions are: EQUALITY = “as…as.” DIFFERENCE = “more/less…than.” Never substitute one conjunction for the other.

Eight Worked Examples: Logical Comparisons and Idioms Combined

The following examples combine both concepts as the Digital SAT presents them.

EXAMPLE 1 (Idiom + comparison combined): “The academic credentials of this candidate are different than the other applicants.” ERROR 1: “different than” → “different from” (idiom: “different from” for noun phrases) ERROR 2: “the other applicants” → “those of the other applicants” (comparison: credentials vs applicants; add “those of” to compare credentials to credentials) CORRECT: “The academic credentials of this candidate are different from those of the other applicants.” NOTE: Both errors are fixed in the corrected version. The answer choices on the Digital SAT would offer versions that fix one, both, or neither - the correct answer fixes both.

EXAMPLE 2 (Idiom - verb + preposition): “The new policy prohibits researchers to use unconsented data.” ERROR: “prohibits…to use” should be “prohibits…from using.” CORRECT: “The new policy prohibits researchers from using unconsented data.”

EXAMPLE 3 (Unlike + possessive trap): “Unlike traditional models, the new algorithm’s accuracy is significantly higher.” ERROR: “Unlike traditional models” introduces a comparison of models (systems). Main clause subject: “the new algorithm’s accuracy” (a measurement). Models cannot be compared to accuracy measurements. POSSESSIVE TRAP: “the new algorithm’s accuracy” - “the new algorithm’s” is possessive. The grammatical subject is “accuracy,” not “the algorithm.” CORRECT: “Unlike traditional models, the new algorithm achieves significantly higher accuracy.” “The new algorithm” (a model) is now the main clause subject - comparable to “traditional models.”

EXAMPLE 4 (As…as - CORRECT): “The second study was not as comprehensive as the first.” ANALYSIS: This is CORRECT. “Not as [adjective] as” is the negative form of the “as…as” equality construction. Both elements are correctly parallel (both describe “comprehensive” in comparative relationship). No error.

EXAMPLE 5 (Regard as): “Most scholars regard this text to be the definitive account.” ERROR: “regard…to be” - “to be” is never correct with “regard” in this sense. CORRECT: “Most scholars regard this text as the definitive account.” VERIFICATION: Can you substitute “classify” for “regard”? “Most scholars classify this text as the definitive account.” - “as” works with “classify” too. Both classification verbs take “as.”

EXAMPLE 6 (Quality vs places): “The quality of education in urban districts is often higher than rural districts.” ERROR: “quality of education” (an attribute, a standard) vs “rural districts” (geographic/administrative areas). CORRECT: “The quality of education in urban districts is often higher than that of rural districts.” “That of rural districts” = the quality of education of rural districts → quality compared to quality. EQUAL SIGN TEST: “quality = rural districts” → fails. “quality = that of rural districts” (= quality of rural districts) → passes.

EXAMPLE 7 (Attribute to): “The authors attributed the discrepancy with a flaw in the sampling procedure.” ERROR: “attributed…with” - “with” is not the correct preposition after “attribute.” CORRECT: “The authors attributed the discrepancy to a flaw in the sampling procedure.” MEMORY: Attribution points TO a cause. “Attribute TO” - the attribution goes in the direction of the cause. CONFIRMATION: “Attributed to” is equivalent to “caused by” - you could say “The discrepancy was caused by a flaw” → “attribute TO a flaw.”

EXAMPLE 8 (Compound - idiom + potential comparison): “Her research has been regarded like the most influential contribution to the field, surpassing the work of any other researcher.”

ERROR ANALYSIS: (1) “regarded like” → “regarded as.” “Like” introduces comparisons; “as” is required with “regard.” (2) “surpassing the work of any other researcher” - is this a comparison error? LEFT: “her research” (work). RIGHT: “the work of any other researcher” (also work). Work compared to work → CORRECT. This is not an error.

So only one error exists in this sentence: CORRECT: “Her research has been regarded as the most influential contribution to the field, surpassing the work of any other researcher.”

LESSON: Not every sentence with a comparison word contains a comparison error. Always apply the equal-sign test rather than assuming an error exists. “Surpassing the work of any other researcher” correctly compares work to work.

Extended Idiom Coverage: Additional Patterns

Adjective + Preposition: Additional Pairings

CONTRARY TO (not “contrary of”): “Contrary to popular belief, the findings showed no significant correlation.” “Contrary to the original hypothesis, the intervention showed no measurable effect.” “Contrary to what was expected” - “to” governs the phrase following “contrary.” NOTE: “Contrary to” frequently introduces a sentence that corrects a false assumption - “contrary to X, the reality is Y.” This rhetorical pattern appears often in Digital SAT passages.

CONSISTENT WITH (not “consistent to”): “The results were consistent with the original hypothesis.”

CHARACTERISTIC OF (not “characteristic to” or “characteristic for”): “This pattern is characteristic of populations under resource stress.” “Rapid cell division is characteristic of cancerous tissue.” “Characteristic of” - the characteristic belongs to (is OF) the entity or population described. “Of” indicates this belonging relationship.

INDICATIVE OF (not “indicative to” or “indicative for”): “The early data are indicative of a positive trend.” “A sudden increase in volatility is often indicative of an underlying structural change.” “Indicative of” - something is indicative OF a condition, meaning it points toward that condition as evidence. “Of” signals this evidential pointing relationship.

SUBJECT TO (not “subject of”): “All proposals are subject to committee review.” “The results are subject to revision pending the full dataset analysis.” “Subject to” - to be under the authority or effect of something. “To” indicates direction toward the governing principle or condition.

COMMITTED TO (not “committed for” or “committed in”): “The organization is committed to transparency in reporting.” “The team is committed to completing the study within the proposed timeline.” “Committed to” - commitment is directed TOWARD a goal or principle. “To” captures this directional dedication.

DEDICATED TO (not “dedicated for”): “She has dedicated her career to understanding neurodegenerative diseases.” “The journal is dedicated to publishing research on environmental sustainability.” “Dedicated to” - dedication is directed TOWARD something. Like “committed to,” the “to” captures directionality of purpose.

Verb + Preposition: Additional Pairings

AGREE WITH (a person) / AGREE ON (a topic) / AGREE TO (a proposal): “The researchers agreed with the lead author’s interpretation.” (agreeing with a stated opinion) “The team agreed on a revised timeline.” (reaching consensus on a decision) “Both parties agreed to the new terms.” (accepting a formal proposal) NOTE: The correct preposition changes based on what follows “agree.” This three-way distinction is unusual in the idiom list - most verbs have only one correct preposition. For “agree,” always identify what follows before selecting the preposition.

INSIST ON (not “insist to” or “insist about”): “The reviewer insisted on a complete revision.” “The committee insisted on full transparency throughout the process.” “Insist on” is followed by a noun phrase or gerund: “insisted on revising,” “insisted on completion,” “insisted on her right to appeal.”

OBJECT TO (not “object with” or “object about”): “Several committee members objected to the proposed changes.” “She strongly objected to being excluded from the decision-making process.” “Object to” signals directed opposition - you object in the direction of the thing you oppose. “To” captures this directed relationship.

CONTRIBUTE TO (not “contribute for” or “contribute in”): “Her work contributed to the advancement of the field.” “Each team member contributed to the final report in a meaningful way.” “Contribute to” - contributions go TOWARD something; they move in the direction of the recipient or cause. “To” captures this directional movement.

RELY ON (not “rely to” or “rely with”): “The study relies on self-reported data.” “Effective policy relies on accurate research and reliable data collection.” “Rely on” - reliance rests ON a foundation. You place your trust ON something, as though standing on it. “On” captures this foundational relationship.

CONFORM TO (not “conform with” or “conform by”): “All submissions must conform to the style guidelines.” “The experimental design must conform to the ethical standards established by the review board.” “Conform to” - conformity is alignment toward a standard. You adjust TO fit the standard. “To” signals this directed alignment. NOTE: “Conform with” is occasionally acceptable in British English but “conform to” is the standard tested on the Digital SAT.

“Not Only…But Also” and Idiom Interaction

When idioms appear inside correlative conjunction constructions, both the idiom and the parallel structure must be correct simultaneously.

INCORRECT: “She is not only interested about the data but also committed for the analysis.” TWO ERRORS: “interested about” should be “interested in”; “committed for” should be “committed to.” CORRECT: “She is not only interested in the data but also committed to the analysis.”

INCORRECT: “The study was regarded to be both accurate and consistent to previous findings.” TWO ERRORS: “regarded to be” should be “regarded as”; “consistent to” should be “consistent with.” CORRECT: “The study was regarded as both accurate and consistent with previous findings.”

Extended Comparison Examples: All Patterns at Every Difficulty Level

Pattern 1 Additional: Quantity vs Place (Harder Variants)

HARDER - NESTED POSSESSIVE: INCORRECT: “The rate of economic growth in Singapore has consistently outpaced China.” “Rate of growth” (a metric) vs “China” (a country). Also note: this could be read as Singapore outpacing the country of China rather than its growth rate. CORRECT: “The rate of economic growth in Singapore has consistently outpaced that of China.”
HARDER - EMBEDDED COMPARISON: INCORRECT: “Researchers found that the carbon emissions of developed nations, while declining, still exceed developing nations by a significant margin.” “Carbon emissions” vs “developing nations.” CORRECT: “Researchers found that the carbon emissions of developed nations, while declining, still exceed those of developing nations by a significant margin.”
PASSABLE STRUCTURE (CORRECT): CORRECT: “San Francisco’s housing market is more expensive than Seattle’s.” The possessive “San Francisco’s” and “Seattle’s” both refer to housing markets → market compared to market. No error.

Pattern 4 Additional: “Like” and “Unlike” Harder Variants

HARDER - MULTIPLE NOUNS IN PHRASE: INCORRECT: “Like the most celebrated novels of the Victorian era, the author’s themes explore social inequality.” “Like the most celebrated novels of the Victorian era” (novels, things) vs “the author’s themes” (themes, different things). CORRECT: “Like the most celebrated novels of the Victorian era, this novel explores themes of social inequality.” Now “this novel” (a novel) is compared to “the most celebrated novels.”
HARDER - SUBJECT CONCEALED IN PASSIVE: INCORRECT: “Like many scientific breakthroughs, the discovery was made by accident.” ANALYSIS: “Like many scientific breakthroughs” (breakthroughs/events) vs “the discovery” (also a breakthrough/event). This is actually CORRECT - a discovery is a type of scientific breakthrough, so the comparison is logically valid.
TRICKY - “UNLIKE” WITH POSSESSIVE: INCORRECT: “Unlike her mentor’s cautious approach, she embraced bold experimentation.” “Unlike her mentor’s cautious approach” (an approach) vs “she” (a person). Approaches and people are not comparable. CORRECT: “Unlike her mentor’s cautious approach, her approach embraced bold experimentation.” OR: “Unlike her mentor, she embraced bold experimentation.” (compare persons)

The Comparison Decision Tree

For every comparison question, run this 4-step sequence:

STEP 1: Find the comparison word (“than,” “as…as,” “like,” “unlike,” “similar to,” “compared to,” “different from”). STEP 2: Identify what is on the LEFT side of the comparison - state the category precisely (person, place, quantity, rate, method, finding, policy, etc.). STEP 3: Identify what is on the RIGHT side - state its category. STEP 4: Are both categories the same? If yes → no error. If no → error. Fix: “that of” (singular left noun) / “those of” (plural left noun) / possessive / restructure the sentence.

TIMING: This 4-step sequence takes 5 to 8 seconds once practiced. On the exam, most comparison questions are identifiable and fixable in under 20 seconds.

This 4-step sequence takes 5 to 8 seconds per sentence and is 100% reliable for identifying comparison errors.

Extended Idiom Coverage: Full 25 Idioms with Worked Sentences

Group 1 Extended: Adjective + Preposition

DIFFERENT FROM in a complex sentence: “The experimental results were completely different from what the theoretical model had predicted.” “Different from” followed by a clause - “what the theoretical model had predicted” - is also correct. “Different from” governs both noun phrases and clause complements.

RESPONSIBLE FOR in a compound sentence: “The lead investigator was responsible for coordinating data collection, managing the team, and submitting the final report.” “Responsible for” governs all three gerund phrases in the list. The idiom must remain consistent across all items - “responsible for [gerund]” throughout.

CAPABLE OF in a comparative context: “The new instrument is capable of detecting concentrations ten times lower than its predecessor.” “Capable of detecting” - gerund following the idiom is the standard construction.

FAMILIAR WITH combined with comparatives: “Most researchers in the field are familiar with the foundational studies but less familiar with recent replication attempts.” “Familiar with” repeated in both arms; note that “less familiar with” correctly maintains the idiom across the comparison. Both arms use “with.”

INDEPENDENT OF with intensifiers: “The control group’s outcomes were entirely independent of any intervention, as intended by the study design.” “Independent of” with an intensifier (“entirely”) - the preposition stays the same regardless of the modifier. “Completely independent of,” “largely independent of,” “wholly independent of” all follow the same pattern.

Group 2 Extended: Verb + Preposition

REGARD AS in passive constructions: “This 1962 paper is widely regarded as the foundational text for the entire discipline.” “Regarded as” in passive voice: the idiom remains “as” even when the verb is passive. “Regarded to be” is wrong whether active or passive.

ATTRIBUTE TO with multiple attributions: “The improvement in outcomes can be attributed to better early detection, improved treatment protocols, and greater patient compliance.” “Attributed to” governs all three noun phrases. The preposition “to” applies to the entire list.

PROHIBIT FROM in formal institutional language: “University policy strictly prohibits faculty from serving on dissertation committees for their own graduate students.” “Prohibits faculty from serving” - note that the gerund “serving” follows “from.”

SUCCEED IN with complex gerund phrases: “The research team succeeded in developing a model that accurately predicts the behavior of the compound under various temperature conditions.” “Succeeded in developing” - the gerund follows “in.”

COMPLY WITH in regulatory contexts: “All submitted manuscripts must comply with the journal’s formatting guidelines before peer review begins.” “Comply with” - “with” is followed by the noun phrase “the journal’s formatting guidelines.”

STEM FROM in academic analysis: “Many of the errors in the original dataset appear to stem from inconsistencies in the data entry procedures used during the first year of the study.” “Stem from” - “from” introduces the cause.

DISTINGUISH FROM in scientific writing: “A key challenge in this field is distinguishing correlation from causation based on observational data alone.” “Distinguishing correlation from causation” - the preposition “from” separates the two things being distinguished.

Group 3 Extended: Noun + Preposition

BAN ON in policy contexts: “The 2021 legislation imposed a comprehensive ban on the use of certain industrial chemicals in consumer products.” “Ban on” - “on” governs the thing that is banned.

CONCERN ABOUT in academic discourse: “Concerns about reproducibility have prompted major journals to require data sharing as a condition of publication.” “Concerns about” - note the plural “concerns” is natural; the preposition remains “about.”

DEBATE OVER / ABOUT in scholarly contexts: “The debate over whether artificial intelligence constitutes genuine intelligence remains unresolved in the philosophy of mind literature.” “Debate over whether” - “over” can precede a clause introduced by “whether.”

Group 4 Extended: Phrase Constructions

AS…AS in negative constructions: “The second trial was not as well-controlled as the first, which limits the comparability of the results.” “Not as well-controlled as” - negative “as…as” construction is correct.

MORE…THAN in multi-part comparisons: “The integrated approach proved more effective, more cost-efficient, and more scalable than any of the single-strategy alternatives.” “More [adjective], more [adjective], and more [adjective] than” - the parallel construction maintains “more…than” throughout.

NOT SO MUCH…AS with noun phrases: “The problem was not so much a lack of data as an inability to interpret the available evidence correctly.” “Not so much [noun phrase] as [noun phrase]” - the standard pattern with two noun phrases.

Idiom Groups by Difficulty Level

For exam preparation, the 25 idioms can be organized by how frequently they appear and how tricky the wrong forms are.

HIGHEST PRIORITY (most frequently tested, most commonly confused):

Different FROM (vs “different than”) - appears in comparison and description contexts
Regard AS (vs “regard to be”) - appears in academic evaluation contexts
Prohibit FROM (vs “prohibit to”) - appears in policy and regulatory contexts
Capable OF (vs “capable to”) - appears in description of abilities or features
Attribute TO (vs “attribute with”) - appears in causal analysis contexts
Succeed IN (vs “succeed at”) - appears in achievement contexts

MODERATE PRIORITY (regularly tested):

Responsible FOR - “The team is responsible for quality control” (not “responsible of”)
Comply WITH - “All submissions must comply with guidelines” (not “comply to”)
Similar TO - “This approach is similar to the established method” (not “similar as”)
Familiar WITH - “The researcher is familiar with the literature” (not “familiar of”)
Independent OF - “Results independent of external factors” (not “independent from”)
Consistent WITH - “Findings consistent with the hypothesis” (not “consistent to”)
Contribute TO - “Her work contributed to the field” (not “contribute for”)
Rely ON - “The model relies on three assumptions” (not “rely to”)
Ban ON - “A ban on certain substances” (not “ban against”)

SUPPORTING KNOWLEDGE (tested less frequently but worth knowing):

Debate OVER/ABOUT - “The debate over methodology” or “debate about findings”
Insist ON - “The reviewer insisted on a complete revision” (not “insist to”)
Object TO - “Members objected to the proposed changes” (not “object with”)
Contrary TO - “Contrary to popular belief, the data shows…” (not “contrary of”)
Characteristic OF - “A pattern characteristic of stress responses” (not “characteristic to”)
Indicative OF - “Results indicative of a positive trend” (not “indicative to”)
Dedicated TO - “Dedicated to advancing research” (not “dedicated for”)
Concerned ABOUT / WITH - “Concerned about reproducibility” or “concerned with methodology”
Stem FROM - “Errors stem from inconsistent procedures” (not “stem in”)
Distinguish FROM - “Distinguish correlation from causation” (not “distinguish than”)

The Comparison-Idiom Connection

Logical comparisons and idiomatic expressions are grouped in this article because they share a preparation principle: both require explicit memorization of correct forms that sound natural in their wrong versions. Neither can be fully prepared for through rule application alone.

Logical comparisons require memorizing the “that of / those of” fix and the principle of like-to-like comparison. Idiomatic expressions require memorizing the 25 preposition pairings. In both cases, the preparation is finite and the payoff is complete: once memorized, every comparison question and every idiom question has a clearly correct answer that the prepared student can identify rapidly.

Together, these two question types account for roughly 15% of all Digital SAT Writing questions. A student who has mastered both achieves reliable correct answers on a meaningful proportion of the section with preparation that is entirely within their control.

Practice Protocol

PHASE 1: MEMORIZATION (first week) Memorize the 25 idiom pairings using flashcards or spaced repetition. For each idiom, create one example sentence using the correct form and one showing the wrong form. Writing both versions reinforces why the wrong form is wrong.

For the 25 idioms, group them by priority: memorize the six highest-priority pairings first (different from, regard as, prohibit from, capable of, attribute to, succeed in). These six are tested most frequently and produce the highest return on memorization time. Then add the moderate-priority group (9 more pairings), then the supporting group (10 more). This staged approach ensures the most tested idioms are locked in first.

For comparison patterns, practice the equal-sign test on ten sentences per day. Write out the two things being compared and draw the equal sign: “GDP = France” (fails) → error. “GDP = that of France” (passes) → correct.

PHASE 2: RECOGNITION PRACTICE (second week) Complete 20 idiom questions and 20 comparison questions per day, focusing on identifying the error type before reading the answer choices.

For comparison questions: before reading the answer choices, identify both sides of the comparison and apply the equal-sign test. Write out “LEFT = RIGHT” and determine whether it holds. If not, determine whether the fix requires “that of,” “those of,” a possessive, or restructuring. Then read the answer choices and select the one matching your predetermined fix. For idioms: identify the central word (verb, adjective, noun) and recall the correct preposition. For comparisons: apply the equal-sign test before reading choices.

PHASE 3: TIMED INTEGRATION (third week) Complete full Writing modules under timed conditions. Idiom questions should resolve in 10 to 20 seconds (recall the correct form, select it). Comparison questions should resolve in 15 to 25 seconds (equal-sign test, identify fix, select correct answer). These are among the most time-efficient questions on the Writing section once the knowledge is solid.

A benchmark for completion: a student who can identify and categorize every error in this article’s 25 idioms and 21 comparison examples without hesitation is ready for the exam. That recognition speed is the product of the memorization and practice protocol described in Phase 1 and Phase 2.

Frequently Asked Questions

Q1: What is the most reliable test for a faulty comparison?

Draw a mental equal sign between the two things being compared. If they cannot logically be equivalent, the comparison is faulty. “The population of Texas = California” - a population cannot equal a state; the comparison is faulty. “The population of Texas = that of California” - a population equals another population; the comparison is valid. This equal-sign test takes two seconds and catches every comparison error. Once students apply it automatically, comparison questions become among the fastest on the Writing section.

Q2: When should I use “that of” vs “those of”?

“That of” refers back to a singular noun. “Those of” refers back to a plural noun. “The conclusion of this study differs from that of previous studies” - “conclusion” is singular → “that of.” “The results of this study surpass those of previous studies” - “results” is plural → “those of.” Check the noun on the left side of the comparison: singular → “that of,” plural → “those of.”

Common singular nouns that require “that of”: approach, method, analysis, conclusion, impact, style, quality, rate, policy, finding (when singular), data (often treated as singular in formal usage). Common plural nouns that require “those of”: results, findings, outcomes, methods (when plural), studies, analyses, conclusions (when plural).

Q3: Is “different than” ever correct?

“Different than” is acceptable before a clause in informal and some formal usage: “The results were different than we expected.” For the Digital SAT, when “different” precedes a noun or noun phrase, “different from” is the correct form: “Her approach is different from the standard method.” When a choice between “different from” and “different than” is offered before a noun, choose “different from.”

A quick rule for exam day: if the answer choices offer “different from” vs “different than,” and what follows is a noun or noun phrase, choose “different from.” This rule is reliable for all Digital SAT contexts.

Q4: How do I remember that “prohibit” takes “from,” not “to”?

Think of the meaning: “prohibit” means “prevent from doing.” When you prevent someone from doing something, the construction is “prevent [someone] from [doing].” Since “prohibit” means the same thing as “prevent,” it follows the same preposition pattern: “prohibit [someone] from [doing].” Any verb meaning “prevent” or “block” takes “from” in this construction.

The full family of “prevent/keep from doing” verbs all take “from”: prevent from, prohibit from, keep from, stop from, deter from, discourage from, bar from. When you see any of these verbs followed by a person and an action, the preposition is always “from.” “Prohibit” belongs to this family.

Q5: What is the difference between “regard as” and “consider as”?

“Regard as” requires “as”: “They regard the study as definitive.” “Consider” can be used without “as” when followed directly by a noun or adjective: “They consider the study definitive” (no “as”). With “as,” both work: “They consider the study as definitive.” The Digital SAT most frequently tests “regard as” - the “to be” version (“regard to be”) is always wrong.

For exam day: whenever you see “regard” in an underlined portion, check whether it is followed by “as” or “to be.” “Regard as” is always correct; “regard to be” is always wrong. This is one of the most reliable eliminations in the idiom category.

Q6: Why is “debate on” less preferred than “debate over” or “debate about”?

“Debate on” is a matter of register: it appears frequently in informal and journalistic usage but is less standard in formal academic English. The Digital SAT’s passages draw from formal academic and scientific writing, where “debate over” and “debate about” are the conventional pairings. When a choice between “debate on” and “debate over/about” appears, prefer “over” or “about.”

For practical purposes: if an answer choice shows “debate on” while another shows “debate over” or “debate about,” and no other difference exists between the choices, select “debate over” or “debate about.” This preference is consistent across Digital SAT question patterns.

Q7: What are the most commonly confused preposition pairings on the Digital SAT?

The highest-frequency confusion pairs are: (1) “different from” vs “different than,” (2) “regard as” vs “regard to be,” (3) “prohibit from” vs “prohibit to,” (4) “capable of” vs “capable to,” (5) “attribute to” vs “attribute with,” and (6) “succeed in” vs “succeed at.” These six pairs account for the majority of idiom questions. Memorizing the correct form of each of these six is the most efficient idiom preparation investment.

A good memorization technique: create a sentence that uses each correct form and a contrasting sentence using the wrong form. Reading both forms repeatedly reinforces why the correct form is correct and helps the wrong form “sound wrong” - the first step toward automatic recognition.

Q8: How does the “like vs as” distinction affect comparison questions?

“Like” introduces a noun for comparison: “Like many successful leaders, she prioritized communication.” What follows “like” must be logically comparable to the main clause subject. “As” introduces a clause or a role/function: “As the lead researcher, she coordinated the team.” On the Digital SAT, the test checks whether what follows “like” is logically comparable to the main clause subject - if not, either restructure the sentence or change “like” to “as [a/the noun].”

A practical tip: after reading a sentence with “like” or “unlike,” ask “what category follows ‘like’?” then “what is the main clause subject’s category?” Same category → correct. Different categories → error. The most common fix is to restructure the main clause so the subject matches the category introduced by “like.”

Q9: Can possessive forms always substitute for “that of”?

Yes, in most cases. “The GDP of China is larger than that of France” = “China’s GDP is larger than France’s.” Both are grammatically correct and compare GDP to GDP. On the Digital SAT, both forms are typically acceptable, and the question will not force a choice between them unless one version creates a different type of error. When both are offered and both are grammatically valid, either is correct.

When the Digital SAT offers a choice between “that of [X]” and a possessive form “[X]’s,” neither is inherently more correct if both compare equivalent things. The test is checking whether the comparison is logical, not which correct form you use. Choose whichever appears in the answer choice alongside an otherwise error-free sentence.

Q10: What is the “not so much…as” construction and why is it tested?

“Not so much…as” is a set phrase meaning “less X and more Y” where X and Y are competing characterizations: “The challenge is not so much the data collection as the interpretation” (interpretation is the more significant challenge, not data collection). The common wrong form substitutes “but” for “as”: “not so much…but.” On the Digital SAT, when you see “not so much,” the second element must be introduced by “as,” not “but” or “than.”

This construction is tested because it is a fixed phrase that many students have never explicitly analyzed. The wrong form (“not so much…but”) sounds natural to English speakers who unconsciously model it on “not X but Y.” Explicit memorization of the complete phrase “not so much X as Y” is the only reliable preparation.

Q11: How do I handle idiom questions when I am unsure of the correct preposition?

Use the substitution test: try several prepositions and evaluate which sounds most naturally formal. Also, think about meaning: “attribute to” makes sense because attribution is assigning something TO a cause. “Prohibit from” makes sense because prohibition prevents someone FROM doing something. The preposition reflects the logical relationship. When uncertain, lean toward “to,” “from,” or “of” - these three are the most common prepositions in academic idiom pairings.

A directional heuristic: prepositions indicate direction or relationship. “From” indicates source or separation. “To” indicates direction or destination. “Of” indicates belonging or origin. “In” indicates location or domain. “On” indicates surface or topic. Applying these directional meanings often reveals which preposition fits the idiom’s meaning.

Q12: Does the “as…as” construction require both elements to be adjectives?

No. “As…as” can link adjectives (“as accurate as”), adverbs (“as quickly as”), nouns (“as much influence as”), or participial phrases (“as thoroughly tested as”). Both sides must be in the same grammatical form. “As accurate as” is correct (both adjectives). “As accurate than” is wrong (“as…than” is never the correct pattern - “more…than” and “as…as” are the two separate constructions).

The key rule: “as…as” signals EQUALITY (the same degree), and “more/less…than” signals INEQUALITY (a different degree). These two constructions must never be mixed. Never “as…than” and never “more…as.”

Q13: What is the “independent of” vs “independent from” distinction?

“Independent of” is the formal standard: “The results were independent of the researcher’s expectations.” “Independent from” appears in informal usage but is not the preferred form in formal academic writing. On the Digital SAT, “independent of” is correct when the meaning is “not affected by” or “separate from.” “Independent from” occasionally appears as a wrong answer distractor.

The distinction parallels the “different from” vs “different than” pattern: both have informal variants that sound natural, but the formal standard tested by the SAT uses specific prepositions. When “independent” appears in an underlined portion, the preposition should be “of.”

Q14: When does “agree” change its preposition?

“Agree” takes different prepositions depending on what it governs: “agree with [a person or opinion],” “agree on [a topic or decision],” “agree to [a proposal or request].” “Agree with the conclusion,” “agree on a timeline,” “agree to the terms.” The Digital SAT may test any of these three patterns. The meaning of “agree” in context determines which preposition is required.

A quick decision guide: WHO or WHAT follows “agree”? A person or stated opinion → “agree with.” A topic, plan, or decision → “agree on.” A specific proposal, condition, or request → “agree to.” When uncertain, read what follows “agree” and identify whether it is a person (with), a topic (on), or a formal proposal (to).

Q15: How do comparison and idiom errors sometimes appear in the same sentence?

A sentence can contain both an illogical comparison and an idiomatic error simultaneously. “Her work is regarded to be more significant than any other researcher in the field” has: (1) “regarded to be” (should be “regarded as”) and (2) “any other researcher” (work vs researcher, should be “that of any other researcher”). On the Digital SAT, the underlined portion will contain one error; the answer choices will fix that error. Reading the entire sentence helps identify whether there are two errors - the question addresses the one in the underlined portion.

For preparation: practice identifying all errors in a sentence, not just the underlined one. This develops full-sentence structural awareness and helps students confirm that the chosen answer choice does not introduce a new error while fixing the underlined one.

Q16: Is “concerned about” or “concerned with” correct?

Both are accepted but have different meanings. “Concerned about” means worried: “She is concerned about the methodology.” “Concerned with” means focused on or dealing with: “This chapter is concerned with the historical context.” On the Digital SAT, the correct form depends on the intended meaning in context. “Concerned of” is always wrong.

For answer choice evaluation: if the sentence is expressing worry or anxiety, “concerned about” is correct. If the sentence is describing focus, scope, or relevance, “concerned with” is correct. When both are offered, the surrounding sentence context determines which meaning is intended.

Q17: What is the fastest way to identify a logical comparison error?

Scan both sides of the comparison word (“than,” “as…as,” “like,” “unlike”). Identify the category of thing on each side (person, place, quantity, process, quality, object). If the categories differ, the comparison is faulty. The fix: add “that of” (singular) or “those of” (plural) to one side, or restructure using possessive forms. The category-identification step takes two to three seconds and immediately identifies whether an error exists.

For speed training: when practicing, verbalize the category scan out loud: “Left side: GDP (a quantity). Right side: France (a country). Different categories - error. Fix: that of France.” Verbalizing the steps while practicing installs them as a mental checklist that eventually operates silently and automatically during the exam.

Q18: Why does the Digital SAT test idioms?

Idiomatic correctness is a marker of formal academic language command. Students who read widely in academic texts absorb correct pairings naturally; those who primarily engage with informal spoken English may internalize incorrect pairings that “sound right.” Students who read widely in academic and professional contexts absorb correct preposition pairings naturally. Students who primarily encounter informal spoken English may have internalized incorrect pairings that “sound right.” The Digital SAT tests idioms to assess whether students have developed the formal language command that academic success requires. Preparation requires explicit memorization of the 25 most tested pairings.

Q19: What is the “so…that” construction and when is it required?

“So [adjective/adverb] that [clause]” expresses a consequence: “The data was so compelling that the committee approved the proposal immediately.” The construction requires “that” to introduce the consequence clause. Wrong: “The data was so compelling as to cause the committee to approve the proposal” (grammatically possible but not the standard construction tested). When “so” introduces an adjective and an answer choice offers both “that” and “as” continuations, choose “that.”

The “so…that” construction is a set phrase tested specifically because students sometimes write “so…as” or “so…which” instead. Memorizing the complete phrase - “so [adjective] that [clause]” - is the most reliable preparation for this pattern.

Q20: How do I approach idiom questions on exam day efficiently?

For idiom questions, scan the underlined portion for the central word (the verb, adjective, or noun) and immediately recall its conventional preposition pairing from the 25 idioms in this guide. If you know the pairing, select the answer choice with the correct preposition in under 15 seconds. If you are unsure, eliminate answer choices with prepositions that clearly sound wrong, then apply the meaning test (which preposition makes logical sense given what the phrase means). The 25 idioms in this guide cover the majority of what the Digital SAT tests; students who have memorized the correct form for each will handle idiom questions with near-perfect accuracy.

Idiom Recognition in Context: Passage-Level Practice

The Digital SAT presents idiom questions within a passage, not as isolated sentences. The following extended paragraphs contain idiom and comparison errors. Read each and identify the errors.

PASSAGE A: “Recent studies have found that the immune responses generated by mRNA vaccines are different than those produced by traditional inactivated-virus vaccines, though both are regarded to be effective against severe illness. Researchers attribute these differences with the distinct mechanisms by which each vaccine type stimulates the immune system. The debate on whether mRNA technology should replace traditional methods entirely continues among immunologists, though most experts agree to a hybrid approach in which both platforms serve different population needs.”

ERRORS IDENTIFIED:

“different than those produced” → “different from those produced” (idiom: “different from” for noun phrases)
“regarded to be effective” → “regarded as effective” (idiom: “regard as” never “regard to be”)
“attribute these differences with” → “attribute these differences to” (idiom: “attribute to” not “attribute with”)
“The debate on whether” → “The debate over whether” (idiom: “debate over/about” preferred over “debate on”)
“agree to a hybrid approach” → “agree on a hybrid approach” (idiom: “agree on” for topics and decisions; “agree to” for proposals/requests)

CORRECTED PASSAGE A: “Recent studies have found that the immune responses generated by mRNA vaccines are different from those produced by traditional inactivated-virus vaccines, though both are regarded as effective against severe illness. Researchers attribute these differences to the distinct mechanisms by which each vaccine type stimulates the immune system. The debate over whether mRNA technology should replace traditional methods entirely continues among immunologists, though most experts agree on a hybrid approach in which both platforms serve different population needs.”

PASSAGE B: “The economic recovery of southern European nations after the 2008 financial crisis was significantly slower than northern Europe. This can be attributed with a combination of structural factors, including higher debt-to-GDP ratios and less diversified export markets. Unlike the recovery programs implemented in Germany, Greece’s austerity measures were broadly considered to be counterproductive by international economic observers, who were deeply concerned of the long-term social consequences of sustained unemployment.”

ERRORS:

“slower than northern Europe” → “slower than that of northern Europe” (recovery vs region)
“attributed with a combination” → “attributed to a combination”
“Unlike the recovery programs implemented in Germany, Greece’s austerity measures” → “Unlike the recovery programs implemented in Germany, those implemented in Greece” OR “Unlike Germany’s recovery programs, Greece’s austerity measures” (programs vs measures - different categories; best: “Unlike Germany’s recovery programs, Greece’s…”)
“considered to be counterproductive” → “considered counterproductive” (or “regarded as counterproductive”)
“concerned of the long-term” → “concerned about the long-term”

The Complete Comparison Correction Method

For any comparison error, the correction follows a three-step method:

STEP 1: IDENTIFY THE LEFT SIDE What is the noun being described before the comparison word? Include the full noun phrase. Example: “The research methodology of this team” → noun = “methodology.”

STEP 2: IDENTIFY THE RIGHT SIDE What follows “than,” “like,” “unlike,” “as,” or “similar to”? Example: “other teams” → a reference to the teams, not their methodologies.

STEP 3: APPLY THE FIX The right side must match the left side’s category. Choose from: A) Add “that of” (singular left noun) or “those of” (plural left noun): “that of other teams” B) Use possessive form: “other teams’” C) Restructure: change the left side to match the right side

FULL EXAMPLE: “The research methodology of this team is more rigorous than other teams.” Step 1: Left noun = “methodology” (singular) Step 2: Right side = “other teams” (teams, not methodologies) Step 3: Fix = “that of other teams” → “The research methodology of this team is more rigorous than that of other teams.”

Common SAT Passage Contexts for Comparisons and Idioms

The Digital SAT draws passages from specific content areas. Knowing which contexts most frequently generate comparison and idiom errors helps students apply the right checks quickly.

SCIENCE PASSAGES: Common comparison traps involve comparing research findings/results/methods to studies rather than to their equivalent findings/results/methods. Common idioms in science contexts: “attribute to,” “consistent with,” “independent of,” “characteristic of,” “indicative of,” “distinguish from.”

HISTORY/SOCIAL STUDIES PASSAGES: Common comparison traps involve comparing economic measures to countries, or comparing a historical figure’s policies to another historical figure rather than to their policies. Common idioms: “different from,” “contrary to,” “responsible for,” “result in.”

HUMANITIES/LITERARY PASSAGES: Common comparison traps involve comparing an author’s style or themes to another author rather than to their style or themes. Common idioms: “regard as,” “similar to,” “dedicated to,” “contribute to.”

ECONOMICS/BUSINESS PASSAGES: Common comparison traps involve comparing prices, rates, or GDP to countries or companies. Common idioms: “succeed in,” “prohibit from,” “comply with,” “rely on,” “account for.”

Scoring Impact

Logical comparison and idiom questions together typically represent five to eight questions per Digital SAT Writing module. These are among the most preparation-responsive question types on the test:

For idioms: once the 25 pairings are memorized, every idiom question resolves in 10 to 15 seconds with near-perfect accuracy. No analysis is required - recognition and recall are the only skills needed.

For comparisons: once the equal-sign test is automatic, every comparison question resolves in 15 to 20 seconds. The fix method (that of / those of / possessive) is equally mechanical once the error is identified.

Combined time budget: with idiom questions taking 10 to 15 seconds each and comparison questions taking 15 to 20 seconds each, a student who has mastered both rule types will complete five to eight of these questions in under two minutes total across a Writing module. The time saved can be redistributed to more complex rhetorical synthesis or expression of ideas questions.

Combined, these two question types can yield 85 to 95% accuracy with two weeks of dedicated preparation - making them among the highest-return preparation investments in the entire Writing section. A student who spends five hours on idiom memorization and three hours on comparison practice is well-positioned to maximize their score on both question types.

The Underlying Principle: Precision in Academic Language

Both logical comparisons and idiomatic expressions are markers of academic language precision - two of the most visible signals that a writer has internalized formal English rather than simply transferred informal speech habits to paper. A writer who compares like to like demonstrates careful, logical thinking - the same precision that makes strong academic arguments. A writer who uses “different from” rather than “different than” demonstrates familiarity with formal academic register, signaling that they have absorbed the conventions of serious scholarly writing.

The Digital SAT tests these skills because they predict success in academic contexts where precision matters: research writing, professional communication, and formal argumentation all require the same habits - comparing equivalent things, using the conventional expression for each relationship.

For students entering university: professors in every discipline use these idioms correctly and expect their students to do the same. An essay that writes “Her results are different than the control group’s” signals informal register; one that writes “Her results are different from those of the control group” signals academic precision. The preparation done for this article develops exactly the language habits that academic life rewards. The preparation done for these question types develops exactly the language precision that academic success requires.

Students who complete this guide’s preparation protocol will handle logical comparison and idiom questions efficiently and accurately, and they will carry the precision habits developed here into all their academic writing. Both rule types are fully learnable, both are directly testable, and both reward preparation over guessing in exactly the way that makes SAT preparation worthwhile. The return on preparation is both immediate (test score) and long-term (writing quality).

Summary: Two Rules, Finite Preparation, High Payoff

LOGICAL COMPARISONS: Compare like to like. Apply the equal-sign test. Use “that of” or “those of” for the fix. Watch for the possessive trap (possessive modifiers conceal the actual subject). Fix with “that of” (singular) or “those of” (plural). Check “like/unlike” comparisons by confirming the main clause subject matches the category introduced by “like/unlike.”

IDIOMATIC EXPRESSIONS: Memorize the 25 preposition pairings in priority order (six highest-priority first). For each idiom question, identify the central word and recall the correct preposition. Select the answer choice with that preposition. For uncertain cases, use the meaning-based reasoning (direction, belonging, alignment) to eliminate wrong prepositions.

Both rule types are finite, testable, and directly improvable through the preparation this guide provides. Together with parallel structure, modifier placement, punctuation, and subject-verb agreement covered in the companion articles, they form the complete Standard English Conventions toolkit for the Digital SAT Writing section.

A student who has completed Articles 38 through 42 of this series has covered: all major grammar rule categories, all punctuation mark selection rules, parallel structure and modifier placement, and now logical comparisons and idiomatic expressions. This is a comprehensive, exam-ready preparation for every question type in the Standard English Conventions domain. Articles 43 and 44 complete the toolkit with verb tense and mood and sentence boundaries.

Additional Idiom Context: Formal vs Informal Prepositions

One theme runs through many of the 25 idiom pairings: the correct formal-academic preposition is often the less intuitive one, while the wrong preposition sounds natural because it appears in informal speech. Understanding this pattern helps students anticipate which prepositions the SAT tests.

FORMAL vs INFORMAL PAIRINGS (formal/SAT correct listed first):

“different FROM” (formal) vs “different than” (informal) - both are widespread; only “from” is correct on the SAT
“succeed IN” (formal) vs “succeed at” (informal) - both heard in everyday speech; “in” is required for the test
“independent OF” (formal) vs “independent from” (informal) - “from” appears in independence-of-a-nation usage; “of” is the academic standard
“debate OVER/ABOUT” (formal) vs “debate on” (informal) - “debate on” appears in journalism; “over/about” is the academic preference
“prohibit FROM” (formal) vs “prohibit to” (never correct but sounds like “allow to”) - the confusion with “allow to” is the primary source of this error
“regard AS” (formal) vs “regard to be” (sounds formal but is incorrect) - hypercorrection creates this error
“consistent WITH” (formal) vs “consistent to” (less standard) - rare error but tested occasionally

When uncertain about a preposition, ask: which form would appear in a peer-reviewed journal or formal policy document? That form is almost always the correct Digital SAT answer.

The Possessive Trap: A Special Warning

The most common reason students miss logical comparison errors is the possessive trap. A sentence like “Like her mentor, her research focused on equity” looks correct at first glance because “her mentor” (a person) is visible in the “like” phrase. But the grammatical subject of the main clause is “her research” (a thing), not “her” (a person). The possessive “her research” obscures this by making the person seem present when in fact only their possessive modifier appears.

THE POSSESSIVE TRAP RULE: A possessive modifier (“her research,” “the company’s strategy,” “Stanford’s endowment”) makes a thing the grammatical subject. Even though a person or organization appears in the possessive form, the subject is the THING possessed, not the possessor.

Examples: “Her research” → subject is “research,” not “her” “The company’s policy” → subject is “policy,” not “the company” “Stanford’s endowment” → subject is “endowment,” not “Stanford” “The study’s findings” → subject is “findings,” not “the study”

When a sentence opens with “Like [person/organization],” the main clause subject must be that same type of entity - a person or organization, not a thing they possess. Sentences where the possessive creates a false impression of the correct subject type are the hardest comparison questions on the Digital SAT.

WORKED EXAMPLE: “Like many pioneering scientists of the 20th century, her work challenged established orthodoxies.” ERROR: “Like many pioneering scientists” (people) vs “her work” (things/output). FIX: “Like many pioneering scientists of the 20th century, she challenged established orthodoxies through her work.”

“Like the leading economists of her era, her predictions proved remarkably accurate.” ANALYSIS: “Like the leading economists” (people) vs “her predictions” (things). But wait - is there a person in the main clause? “Her predictions” - possessive trap. The subject is “predictions,” not “her.” FIX: “Like the leading economists of her era, she made predictions that proved remarkably accurate.”

Summary Table: Quick Reference

Comparison Type	Example Error	Fix
Quantity vs Place	GDP of China > United States	GDP > that of the United States
Salary vs Person	Salary of X > a lawyer	Salary of X > that of a lawyer
Method vs Study	Methods > the 2019 study	Methods > those of the 2019 study
Like + wrong category	Like scientists, her work…	Like scientists, she…
Unlike + wrong category	Unlike policies, the director…	Unlike her predecessor, the director…
Plural reference	Results > rival teams	Results > those of rival teams

Idiom	Correct	Common Wrong Form
different	different FROM	different than
regard	regard AS	regard to be
prohibit	prohibit FROM doing	prohibit to do
capable	capable OF	capable to
attribute	attribute TO	attribute with
succeed	succeed IN	succeed at
responsible	responsible FOR	responsible of
comply	comply WITH	comply to
independent	independent OF	independent from
ban	ban ON	ban against
debate	debate OVER/ABOUT	debate on
not so much	not so much X AS Y	not so much X but Y
as…as	as X AS Y	as X than Y
more/less…than	more X THAN Y	more X as Y

Mastering both rules in this guide - the six comparison patterns and the 25 idiom pairings - prepares a student for every logical comparison and idiomatic expression question the Digital SAT presents. Together with the grammar rules in Articles 38 through 41 and 43 through 44, these two rule sets complete the Standard English Conventions toolkit for the Writing section.

Article 42 at a Glance: The Essential Checklist

FOR EVERY COMPARISON QUESTION:

Find the comparison word (than, as…as, like, unlike, similar to, different from).
Identify the category on the LEFT side.
Identify the category on the RIGHT side.
Same category? No error. Different categories? Fix with “that of” (singular), “those of” (plural), possessive form, or restructure.
Watch for the possessive trap: “her research” has “research” as subject, not “her.”

FOR EVERY IDIOM QUESTION:

Find the central word in the underlined portion (verb, adjective, or noun).
Recall its correct preposition pairing from the 25 idioms listed in this guide.
Select the answer choice with that preposition.
If uncertain, use meaning-based reasoning: direction/destination = “to/from,” belonging/possession = “of,” mutual alignment = “with,” location or activity domain = “in/on.”
Eliminate any answer choice whose preposition creates a clearly non-idiomatic phrase.

These two checklists, applied automatically, resolve every logical comparison and idiomatic expression question on the Digital SAT Writing section.

One Final Note: Why These Rules Reward Preparation More Than Most

Most reading comprehension and rhetorical analysis questions cannot be fully “prepared” - they require in-the-moment reasoning about specific texts. But logical comparison and idiomatic expression questions are different: they reward explicit prior knowledge over real-time reasoning.

A student who has memorized the 25 idiom pairings will answer every idiom question correctly. A student who has internalized the equal-sign test and the “that of/those of” fix will answer every comparison question correctly. These are not questions where more intelligent students do better - they are questions where more prepared students do better.

This makes them among the highest-return investments in SAT preparation. The time spent with this guide is time that directly and reliably converts to correct answers on exam day.

Words That Trigger the Equal-Sign Test

For speed on exam day, train yourself to apply the equal-sign test automatically whenever you see any of these words or phrases in an underlined portion or near an answer choice blank:

than
as [adjective] as
like / unlike
similar to / dissimilar to
different from
compared to / compared with
more [adjective] than / less [adjective] than
higher than / lower than / greater than / fewer than
the same as

Any of these triggers should immediately prompt: “What is on the left? What is on the right? Same category?” This automatic triggering, combined with the equal-sign test, makes logical comparison questions among the most efficiently handled questions in the Writing section for a prepared student.

Mastering these two rule types - logical comparisons and idiomatic expressions - produces reliable, efficient, high-accuracy performance on a significant portion of every Digital SAT Writing section. The preparation is finite, the rules are learnable, and the payoff is direct.

For students who have completed this article alongside Articles 38, 39, 40, and 41 of this series: every major grammar and usage rule category for the Digital SAT Writing section is now covered. Articles 43 and 44 complete the preparation with verb tense and mood (Article 43) and sentence boundaries (Article 44), rounding out the complete toolkit.

With 25 idioms memorized and the equal-sign test automatic, a student handles these question types with the speed and confidence that comes from complete preparation - not hope.