Faulty and Logical Comparisons

American Diploma › Digital SAT Reading and Writing — Complete Course

What this question type tests

Comparison questions sit in Standard English Conventions, the grammar-and-punctuation domain of the Reading and Writing section (about 26% of the scored questions, usually 11–15 of them). The official skill list does not name comparisons as a separate skill, but they are part of writing sentences whose form and sense are correct: a comparison that compares the wrong things is not logical, and the choices often differ only in a possessive (Alexandria / Alexandria's), a pronoun (that / those) or a word form (more / most). Grammar questions usually come after the reading questions in each module.

The stem is the usual one: "Which choice completes the text so that it conforms to the conventions of Standard English?" Look for comparison signals: than, as… as, like, unlike, compared with, similar to, different from, and words ending in -er / -est or starting with more / most.

Rule 1: Compare like with like

You can only compare things of the same kind: a population with a population, a price with a price, a person with a person. The most common mistake compares a feature of one thing with the whole of another thing. Ask: What exactly is being compared on the left side? Is the right side the same kind of thing?

• ✗ The population of Cairo is larger than Alexandria. (population compared with a city)
• ✓ The population of Cairo is larger than that of Alexandria. (that = the population)
• ✓ Cairo's population is larger than Alexandria's. (Alexandria's = Alexandria's population)
• ✗ The shells of desert snails are thicker than coastal snails. (shells compared with snails)
• ✓ The shells of desert snails are thicker than those of coastal snails. (those = the shells)
• ✗ Mona's handwriting is neater than her brother. (handwriting compared with a person)
• ✓ Mona's handwriting is neater than her brother's.

Rule 2: That of, those of, or a possessive

To avoid repeating the noun, English uses three tools. Choose by number (singular or plural) and keep the sentence logical.

• ✗ The rules of chess are more complex than that of checkers. (rules is plural → those of)
• ✗ Karim's score was higher than that of Mona's. (double possessive: use "that of Mona" or "Mona's", never both)
• ✗ The number of visitors in 2025 was higher than those in 2020. (number is singular → that)

Tip: replace "that" or "those" with the noun it stands for and read the sentence again: "higher than the number in 2020" ✓.

Rule 3: Like, unlike, compared with — at the start of a sentence

An opener such as Like…, Unlike…, Compared with…, Similar to… is both a comparison and an introductory modifier. The noun right after the comma must be the same kind of thing as the noun in the opener.

• ✗ Unlike the earlier model's battery, the new tablet can run all day. (battery compared with tablet)
• ✓ Unlike the earlier model, the new tablet can run all day. (model vs model)
• ✗ Like the ancient Egyptians, cats were kept in many Roman homes. (people compared with cats)
• ✓ Like the ancient Egyptians, many Romans kept cats in their homes. (people vs people)
• ✗ Compared with last year's exam, students found this year's easier. (exam vs students)
• ✓ Compared with last year's exam, this year's was easier.

Rule 4: "Than any other" and "than anyone else"

When you compare one member of a group with the rest of the same group, add other or else. Without it, the sentence says the thing is bigger than itself.

• ✗ Nour read more books than any student in her class. (Nour is a student in her class, so she read more than herself?)
• ✓ Nour read more books than any other student in her class.
• ✓ Nour read more books than any student in the other classes. (She is not in that group, so no "other" is needed.)
• ✗ Our team scored more than anyone in the league. → ✓ more than any other team in the league.
• ✓ The coach worked harder than anyone else.

Rule 5: Comparative or superlative?

Use the comparative (-er / more / less) for two things and the superlative (-est / most / least) for three or more. Never use both endings at once.

• ✗ Of the two designs, the judges chose the most practical one. → ✓ the more practical one (two designs)
• ✗ Of the three proposals, the committee chose the cheaper one. → ✓ the cheapest one (three proposals)
• ✗ The new train is more faster than the old one. → ✓ faster (never more + -er)
• ✗ This is the most easiest route. → ✓ the easiest route

Rule 6: Complete the comparison with the right partner word

• -er / more … than: taller than, more useful than — never "taller then" (then = time).
• as … as: as tall as, as much rain as — never "as tall than".
• different from: "Her method is different from mine" (the safest choice in formal writing).
• the same as / similar to: "the same as last year", "similar to a lemon".
• Finish the comparison: "The new phone is cheaper" is fine only if the text already says cheaper than what; otherwise add "than the old one".

The 3-step method for test day

1. Spot the comparison signal: than, as… as, like, unlike, compared with, -er/-est, more/most.
2. Name the two things being compared. Read the left side and find its head noun (population, shells, score). Then check that the blank gives the same kind of thing — and the same number (that for singular, those for plural).
3. Check the form: two things → comparative; three or more → superlative; same group → any other; correct partner word (than / as / from).

Worked examples

Worked example 1: those of

Snails that live in the dry hills of Sinai must protect themselves from heat and from birds. In a recent survey, researchers measured hundreds of snail shells and found that the shells of snails collected in the hills were thicker than ______ collected near the coast.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) snails
• B) those of snails
• C) that of snails
• D) the snail

Worked example 2: than any other

Every year, students at a secondary school in Assiut take part in a reading challenge. This year, Nour read more books than ______ in her class, finishing 64 titles before the summer holiday.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) any student
• B) all students
• C) every student's
• D) any other student

Worked example 3: comparative or superlative

A youth council in Ismailia asked architects to suggest ideas for a new sports center. Of the two designs that reached the final round, the council chose the ______ one, a plan that uses natural light instead of expensive lamps.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) more practical
• B) most practical
• C) practicaler
• D) more practicaler

Worked example 4: an unlike opener

The young painter Ahmed Samir trained for years in the studio of a well-known artist who used only soft browns and greys. Unlike the paintings of his teacher, ______ bright, almost electric colors.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) Ahmed likes to use
• B) the young artist Ahmed uses
• C) Ahmed's paintings are full of
• D) Ahmed's style is to use

Practice

All pages in this course

Start here

• The Digital SAT: Complete Overview
• Time Strategy and How to Attack Every Question

Craft and Structure

• Words in Context
• High-Value Vocabulary for SAT Reading and Writing
• Text Structure and Purpose
• Cross-Text Connections

Information and Ideas

• Central Ideas and Details
• Command of Evidence: Textual
• Command of Evidence: Quantitative
• Inferences

Standard English Conventions

• Sentence Boundaries
• Extra Information: Commas, Dashes and Brackets in Pairs
• Commas: Introductions, Lists, Adjectives — and When NOT to Use One
• Semicolons: Joining Two Complete Sentences
• Colons: After a Complete Sentence
• Dashes — and Choosing Between , ; : —
• Subject–Verb Agreement
• Pronoun–Antecedent Agreement, Clarity and Consistency
• Pronoun Case and Sound-Alike Pronouns
• Verb Tense and Aspect
• Verb Finiteness: Gerunds, Participles and Infinitives
• Dangling and Misplaced Modifiers
• Parallel Structure
• Faulty and Logical Comparisons
• Plurals and Possessives

Expression of Ideas

• Transitions
• Rhetorical Synthesis (Student Notes)

Full practice tests

• Digital SAT Reading and Writing — Practice Test 1
• Digital SAT Reading and Writing — Practice Test 2
• Digital SAT Reading and Writing — Practice Test 3