What does a GMAT Focus Strengthen stem actually ask you to…

The GMAT Focus Critical Reasoning section tests a single skill in five different costumes: the ability to see the gap between an argument's evidence and its conclusion, then to act on that gap in a direction the stem specifies. The Strengthen question is the most often misclassified of those five. Candidates read the stem, scan for anything that sounds plausible, and pick the answer that most reinforces the conclusion as they remember it. The cost of that habit shows up as a stuck Verbal score somewhere in the mid-70s, where a candidate can paraphrase an argument yet cannot pick the right one of two adjacent options. The fix is not more practice sets. The fix is a reading protocol that diagnoses the gap before the candidate ever looks at the answer choices. This article walks through that protocol stem-first, then breaks down the five argument shapes that account for almost every Strengthen item a candidate will see on test day.

What a Strengthen stem is actually asking you to defend

A Strengthen question on the GMAT Focus presents an argument with an explicit conclusion and a set of premises that support that conclusion. The stem then asks which of five answer choices would most strengthen the argument. The verb matters. The question is not asking you to confirm the conclusion is true in the real world, nor to add new facts, nor to repeat the premises. It is asking you to identify the choice that, if added as a premise, would close the largest logical gap between the evidence on the page and the conclusion the author is drawing.

The single most common error in the early weeks of preparation is to treat Strengthen as a synonym for "true" or "supportive-sounding". A candidate scans a choice, sees language that flatters the conclusion, and selects it without first naming the gap. In my experience this single habit costs candidates two to three points per section, because at least one distractor in every Strengthen item is engineered to sound supportive while actually doing nothing for the argument's structure. The reading protocol below is built to defeat that distractor before the candidate ever reads choice A.

Three structural features of a Strengthen stem are worth memorising before you ever touch a practice set. First, the stem language is fixed: it asks what would most strengthen, not what would prove, not what would be implied, not what would follow. The fixed vocabulary is your friend; on the GMAT Focus the test-writer cannot rephrase the task. Second, the conclusion is always explicitly stated in the passage, usually in a sentence beginning with a signalling word such as "therefore", "thus", "so", "hence", or "consequently". If you cannot find the conclusion, you have not yet read the passage, you have skimmed it. Third, at least one of the five answer choices will be a near-tautology, restating the conclusion or one of the premises in slightly different vocabulary. Naming that choice as a tautology before you evaluate the rest is a reliable first-pass filter.

The gap-first reading protocol in three moves

Move one is to locate the conclusion in the first 15 seconds. Read only the final sentence, then read any sentence that contains a signalling word. Write the conclusion in your own words on the scratch pad; do not paraphrase silently, write it. The act of writing forces a paraphrase that you can test against the choices later. Move two is to extract the premise set, which is everything that is not the conclusion. List the premises as bare claims, stripping the connective tissue. Move three is to ask one question, in writing: what premise would a sceptic demand that I have not yet been given? The answer to that question is the gap, and the correct answer choice is the option that fills it. The whole sequence runs under 90 seconds once it is internalised, and it is the only protocol that consistently defeats the supportive-sounding distractor.

The five structural shapes of a Strengthen argument

Almost every Strengthen argument on the GMAT Focus fits one of five structural shapes, and recognising the shape collapses the gap diagnosis from a 60-second task into a 10-second task. The shapes are not theoretical; they are the only argument structures the test-writer has room to construct under the time pressure of test design. Memorising the five lets you skip the gap-diagnosis step on items where the shape is obvious and spend that recovered time on the one or two items per section where the shape is genuinely ambiguous.

Shape 1: causal claim defended by correlation

The argument says X causes Y, but the evidence on the page is a correlation, a co-occurrence, or a temporal sequence. The gap is the missing causal link, and the strengthen task is to supply evidence that rules out the obvious alternative explanations. The correct choice on a Shape 1 item typically introduces a control group, a controlled experiment, or a mechanism by which X would produce Y. The classic distractor is a choice that adds more correlation: another population in which X and Y co-occurred, or a historical example where both were present. That distractor closes no gap; the gap was never about whether X and Y co-occur, it was about whether X causes Y. For most candidates this is the single highest-yield shape to drill, because the supportive-sounding distractor is unusually tempting.

Shape 2: survey or sample generalising to a population

The argument draws a conclusion about a whole population from a sample, a poll, or a small case study. The gap is the representativeness of the sample, and the correct choice supplies evidence that the sample mirrors the population on a relevant variable. The distractor offers a third sample, a different methodology, or a critic's objection, none of which addresses whether the original sample is representative. A useful shortcut: if the conclusion contains a quantifier such as "most", "all", "the majority", or "typically", and the evidence is a single case, the gap is representativeness until proven otherwise.

Shape 3: plan or proposal defended by analogy

The argument recommends a course of action because a similar course of action produced a desired outcome elsewhere. The gap is the relevance of the analogy: are the two cases similar on the variable that drove the outcome? The correct choice supplies that similarity explicitly. The distractor supplies another case where the plan worked, which restates the existing evidence rather than closing the gap. This shape is the easiest to misread as Weaken rather than Strengthen, because the candidate is hunting for differences. On a Strengthen stem the question is not "are these cases different?" but "is the variable that matters the same?"

Shape 4: prediction defended by trend extrapolation

The argument projects a future state from a past trend, often with a numeric or rate-based claim. The gap is the assumption that the trend continues, and the correct choice supplies a reason it would. The distractor is a piece of evidence that the trend has been steep in the past, which restates the premise. Shape 4 is the shape on which most candidates waste the most time, because the conclusion and the gap can look identical at a casual read. The diagnostic question is always: what would have to be true for the projection to hold? The answer is your gap.

Shape 5: definition or classification defended by attribute

The argument classifies X as a member of category Y on the basis of one or two attributes, then draws a conclusion that depends on other attributes of Y. The gap is that the listed attributes do not entail the conclusion. The correct choice adds the missing attribute. The distractor offers a second example of X, or a second attribute that is irrelevant to the conclusion's logic. Shape 5 is rare on the GMAT Focus but appears at least once per section for high scorers working through the V85+ band, and the gap-diagnosis protocol handles it cleanly once the candidate stops treating the argument as common-sense and starts reading it as a list of claims.

How to read the answer choices without losing the first 30 seconds

Even with a clean gap diagnosis, candidates lose Strengthen points in the answer-choice phase for two reasons. The first is reading all five choices in full, which costs 40 to 60 seconds and burns clock on a Verbal section where each item is budgeted at roughly 2 minutes. The second is failing to predict the correct answer in the gap-filling language before scanning, then falling for the first choice that sounds plausible. Both are habits, and both are unlearnable in a single sitting. They are, however, replaceable in three to four focused study sessions if the candidate uses the following sequence.

Step one: write a one-sentence prediction

After naming the gap, write a single sentence on the scratch pad describing the kind of evidence that would close it. The sentence need not match GMAT prose; it needs to match your own vocabulary. "A controlled experiment showing X produces Y when all other variables are held constant" is a perfectly good prediction. "Another example where X and Y co-occurred" is a perfectly good prediction of the distractor. The point is to externalise the prediction so that choice scanning becomes a matching task, not a judgement task. A candidate who has written a prediction reads choices in roughly 10 to 12 seconds each. A candidate who has not reads them in 25 to 30 seconds each, because every choice triggers fresh evaluation.

Step two: scan for the gap-filler, not for the "most true" choice

Read each choice only far enough to decide whether it addresses the gap. If it does not, eliminate it without finishing the sentence. Most distractors in Strengthen items are eliminated by the first clause, and the second clause is filler designed to make the choice look thorough. Resist the temptation to read the whole sentence before deciding. The test-writer is betting that you will, because thorough reading feels like careful work. It is not careful work; it is clock loss.

Step three: when two choices both seem to fill the gap, pick the more direct one

On roughly one in five Strengthen items, two answer choices will both appear to address the gap. The tie-breaker is directness. The choice that fills the gap in one inferential step is correct over the choice that fills it in two. A direct filler names the missing premise. An indirect filler restates the conclusion or borrows authority from a source. For most candidates this tie-breaker resolves the item in under 15 seconds, because the indirect filler is the one that sounds more authoritative, more confident, more textbook-like. The correct choice is usually the one that feels slightly under-written by comparison.

Common pitfalls and how to avoid them

Three pitfalls account for the majority of Strengthen errors. The first is the supportive-sound fallacy, where the candidate picks the choice that flatters the conclusion rather than the one that closes the gap. The fix is the prediction step. The second is the tautology trap, where the candidate picks a choice that restates the conclusion as a premise. The fix is to read the conclusion and the choice side by side on the scratch pad: if the choice says the same thing in different words, it is a tautology and is wrong by definition. The third is the reverse-direction trap, where the candidate picks a choice that would weaken rather than strengthen, usually because the choice raises an objection the candidate finds persuasive. The fix is to evaluate each choice against the gap, not against your own opinion of the argument. A choice that you find persuasive may still be a Weaken; the stem is asking for Strengthen.

A fourth pitfall, less common but more expensive when it hits, is the assumption-confusion pitfall. The candidate treats the unstated assumption as if it were the gap, then picks a choice that defends the assumption rather than fills the gap. The distinction is subtle but testable. The assumption is a claim that, if added, would make the argument valid. The gap is the claim that, if added, would make the argument persuasive. On Strengthen items the answer is almost always the gap, not the assumption. On Assumption items the answer is the assumption. Mixing the two is one of the fastest ways to drop from V80 to V72 in a single section.

Time pressure is a fifth pitfall that does not appear in the choices but appears in the score report. A candidate who spends 3 minutes on a single Strengthen item and rushes the next two is a candidate who loses three points to recover one. The Verbal section on the GMAT Focus is paced at roughly 2 minutes per item including reading time. If a Strengthen item has crossed the 2.5-minute mark and the candidate has not yet named a final answer, the correct tactical move is to pick the most gap-filling of the choices read so far, mark the item for review, and move on. TestPrep Europe's diagnostic assessment is calibrated to expose this exact pattern, and most candidates who take it once identify a pacing leak that costs them a Verbal band within the first ten items.

A worked example showing the full protocol

Consider the following argument, written in the style of a GMAT Focus Strengthen item. Newspaper X reported that a new vaccine reduces the incidence of disease Y by 30 percent in patients over 65. Therefore, the vaccine should be made available to all adults, not only to those over 65. The argument is best illustrated by the following. Now work the protocol. Move one, locate the conclusion: the vaccine should be made available to all adults. Move two, extract the premises: (a) the vaccine reduces incidence of disease Y by 30 percent in patients over 65, and (b) a newspaper reported this. Move three, name the gap: the candidate's scratch pad should read, "the 30 percent reduction in over-65 patients would also occur in younger adults." The conclusion depends on that extrapolation, and the evidence on the page only covers the over-65 population.

Now scan the choices. Choice A: the vaccine has been tested in clinical trials for over a decade. This addresses safety, not the age-extrapolation gap. Eliminate after the first clause. Choice B: in a separate study, patients aged 40 to 64 who received the vaccine showed a 28 percent reduction in incidence of disease Y. This directly fills the gap by supplying evidence in a younger population. Mark as the predicted answer. Choice C: the newspaper's reporting has been fact-checked by independent reviewers. This addresses the reliability of the source, not the gap. Eliminate. Choice D: some adults under 65 are at higher risk of disease Y than the average over-65 patient. This would, if anything, support the conclusion, but it does not address whether the vaccine works in younger adults. Eliminate. Choice E: the vaccine has mild side effects in a small percentage of recipients. Side-effect data does not address efficacy across age groups. Eliminate. The answer is B, identified in under 90 seconds by a candidate who has run the protocol.

The distractor worth dwelling on is D, because it is the choice that most candidates select when they skip the gap-diagnosis step. D is true. D is consistent with the conclusion. D feels supportive. But D does not address the gap, which is efficacy in younger adults. The supportive-sound fallacy is, in this item, the difference between a correct answer and a Verbal band drop of two to three points. TestPrep Europe's Verbal module drills this exact distinction across roughly 40 items in the diagnostic phase, and candidates who complete the module report that the supportive-sound fallacy is the single habit they most needed to break.

Building a 30-day preparation plan for Strengthen accuracy

A 30-day plan that moves a candidate from V72 to V80+ on the back of Strengthen accuracy alone is not a heavy plan. It is, however, a structured one. The plan below assumes a candidate studying roughly 90 minutes per day, six days per week, with one full-length Verbal section on the seventh day. It is a tactical plan, not a syllabus; the candidate is expected to be working through the broader Verbal curriculum in parallel.

Week one: gap-diagnosis drills

Take 20 Strengthen items from the official question bank, untimed, and for each one write the conclusion, list the premises, and name the gap in a single sentence on the scratch pad before looking at the answer choices. Do not score the items in this week. The point is to build the writing habit, not to test it. By day five the gap-naming step should take under 30 seconds per item. By day seven, the candidate should be able to name the shape of the argument (the five shapes from the previous section) in under 10 seconds for roughly two-thirds of the items. This is the week in which most candidates discover that they have been reading arguments rather than diagnosing them.

Week two: prediction and elimination drills

Take another 20 Strengthen items, this time with the gap-diagnosis step in place, and add a written one-sentence prediction before scanning the choices. Score the items. The week-two target is to land within one point of the week-one accuracy, despite the prediction step being new. Most candidates hit this target by day four, because the prediction step is a filter rather than a new task. Items where the prediction does not match any of the five choices are the items worth reviewing; those are the ones where the gap-diagnosis step has slipped.

Week three: timed sets and pacing

Run three sets of 10 Strengthen items at 2 minutes per item. The week-three target is to clear all 30 items within 60 minutes with accuracy at or above week-two levels. Candidates who blow the time budget in week three are typically still writing the gap and the prediction in full sentences; switch to abbreviated notation such as "gap: age-extrap" and "pred: works in under-65s". The protocol must be expressible in shorthand by week three, because the test-day scratch pad does not accept prose.

Week four: mixed Verbal review and full sections

Run two full-length Verbal sections under timed conditions and review every Strengthen item, whether answered correctly or not. The week-four target is a Verbal scaled score at or above 80 on the diagnostic, with no more than two Strengthen errors per section. TestPrep Europe's mock Verbal sections are calibrated to this target, and the post-section review is structured around the five shapes and the four pitfalls above. A candidate who has executed the four-week plan should be in a position to convert Strengthen accuracy into a Verbal band gain on test day.

How Strengthen accuracy translates into a GMAT Focus score band

The GMAT Focus Verbal section reports a scaled score on a band from 60 to 90. Each correct answer moves the candidate within that band, but the movement is not linear. The first few correct answers move the score quickly; the last few move it slowly, because the test adapts. For most candidates, a clean Strengthen accuracy in the 80 to 90 percent range corresponds to a Verbal band in the low 80s when combined with comparable accuracy on Inference and Assumption. A clean Strengthen accuracy in the 70 to 80 percent range corresponds to a band in the mid-70s. Below 70 percent, Strengthen accuracy drags the Verbal band down to the low 70s even when other Critical Reasoning families are strong.

The takeaway for preparation is that Strengthen is a high-leverage family within Critical Reasoning. It is not the only family, but it is the family where the gap-diagnosis protocol produces the cleanest accuracy gains in the shortest time. Candidates who fix Strengthen first typically see a Verbal band gain of 3 to 5 points within a 30-day cycle, with no change to their performance on the other four CR families. That is why the four-week plan above targets Strengthen in isolation rather than mixing it with Weaken, Assumption, Inference, and Evaluate from day one.

How Strengthen interacts with the GMAT Focus adaptive format

The GMAT Focus is an adaptive test, and the adaptive logic has a direct consequence for Strengthen preparation. The first ten Verbal items determine which question bank the test draws from for the remainder of the section. A candidate who scores in the V70 band on the first ten items will see Strengthen items from a difficulty pool designed to separate candidates in the V65 to V75 range. A candidate who scores in the V80 band on the first ten items will see Strengthen items from a pool designed to separate candidates in the V78 to V88 range. The shape of the arguments is the same across the two pools. The distractor quality is what changes.

In the lower pool, the supportive-sound distractor is recognisable after a single read. In the upper pool, the supportive-sound distractor is engineered to require the gap-diagnosis protocol to reject, because the distractor is written to address a closely related but distinct gap. This is the second reason the gap-diagnosis protocol matters: it is the only reading habit that scales into the V85+ band, where the supportive-sound distractor is no longer cruder than the correct answer. Candidates who skip the protocol in week one and try to recover it in week four typically find that the protocol works on the lower pool but breaks down on the upper pool, where the distractor quality has risen.

The adaptive logic also shapes preparation strategy in a more practical sense. A candidate who is consistently scoring in the V75 to V78 range on practice tests is being held there by the difficulty of the Verbal items, not by the percentage of correct answers. To move into the V80+ band, the candidate needs to score high enough on the first ten Verbal items to draw the upper-pool items for the remainder of the section. Strengthen is the family most likely to produce a quick lift in those first ten items, because the gap-diagnosis protocol is teachable in a short cycle and the accuracy gains are visible in the score report within a single sitting.

Test-day tactics for the final 20 minutes of Verbal

The final 20 minutes of the Verbal section are when Strengthen accuracy most often slips, because clock pressure has accumulated and the candidate is reading faster than the protocol allows. The tactical fix is to compress the protocol, not abandon it. In the final 20 minutes, the scratch-pad sequence shrinks to a five-second sketch: write the conclusion in three words, write the gap in three words, then scan for the choice that contains the gap words. The shape diagnosis is skipped. The prediction is skipped. The protocol becomes a keyword filter, and the candidate accepts that one or two of the remaining items will be guessed rather than solved.

For most candidates the right number of guesses in the final 20 minutes is between one and three. More than three means the protocol has been abandoned too early; fewer than one means the candidate is over-investing in items that do not move the scaled score. The guessing posture itself matters: pick the choice that most closely matches the gap diagnosis, mark the item for review, and move on. Do not revisit the item unless the candidate has built up a buffer of 30 seconds or more, which on a Verbal section in the final 20 minutes is rare.

TestPrep Europe's Verbal section review is structured around exactly this pacing question, and candidates who have run the four-week plan above typically find that the final-20-minute tactics are already internalised by the time they reach test day. The diagnostic assessment that closes the plan is a natural starting point for candidates building a sharper preparation plan around Strengthen accuracy on the GMAT Focus Verbal section.

Conclusion and next steps

The GMAT Focus Strengthen question is a fixed-format test of a single skill: the ability to diagnose the gap between an argument's evidence and its conclusion, then to select the choice that closes that gap. The five structural shapes cover almost every argument a candidate will see, and the gap-first reading protocol is the only preparation habit that consistently produces accuracy gains within a 30-day cycle. Candidates who build their preparation around the protocol, drill the shapes, and run timed sets in the second half of the cycle typically clear the V80 band within a single preparation cycle. The next step is a diagnostic that isolates Strengthen accuracy from the rest of the Verbal section, so that the candidate can see whether the gap-diagnosis habit is the bottleneck or whether the bottleneck lies elsewhere in Critical Reasoning.

Frequently asked questions

How many Strengthen questions appear on the GMAT Focus Verbal section?

The GMAT Focus Verbal section draws Critical Reasoning items from a pool that includes Strengthen, Weaken, Assumption, Inference, and Evaluate families. In a typical section of 23 Verbal questions, a candidate can expect between three and five Strengthen items, with the exact count depending on the adaptive difficulty band the test assigns after the first ten items. Candidates targeting V80+ should plan to clear all Strengthen items in the section, because Strengthen is the highest-leverage family for accuracy gains in the first ten items.

What is the difference between a Strengthen question and an Assumption question on the GMAT Focus?

Both items test the gap between evidence and conclusion, but the verb differs. A Strengthen question asks which choice, if added as a premise, would most increase the argument's persuasiveness. An Assumption question asks which choice is a claim that must be true for the argument to hold, but is not stated on the page. The distinction matters in answer selection: a Strengthen choice fills the gap, while an Assumption choice names the gap. Candidates who confuse the two typically pick a choice that defends the assumption rather than fills the gap, which is a Verbal band drop of two to three points.

Can a candidate reach V80 on the GMAT Focus without strong Strengthen accuracy?

In practice, a candidate who is below 70 percent accuracy on Strengthen will struggle to clear V80 even with strong performance on other Critical Reasoning families. The Verbal section is adaptive, and Strengthen accuracy is a strong signal in the first ten items that the test uses to assign the difficulty band. For most candidates, fixing Strengthen accuracy first is the fastest path into the V80+ band, because the gap-diagnosis protocol is teachable in a 30-day cycle and the accuracy gains show up in the score report within a single preparation cycle.

How long should a candidate spend on each Strengthen item on test day?

The Verbal section on the GMAT Focus is paced at roughly 2 minutes per item, including reading time. A candidate should aim to clear most Strengthen items in under 2 minutes, with the most diagnostically clean items closed in 60 to 90 seconds. Items that cross the 2.5-minute mark without a clear answer choice are candidates for the final-20-minute guessing posture: pick the most gap-filling of the choices read so far, mark the item for review, and move on. Clock discipline on Strengthen items is itself a scored skill, because the adaptive test rewards candidates who clear the first ten items quickly and accurately.

Does Strengthen accuracy transfer from the classic GMAT to the GMAT Focus?

The five structural shapes of a Strengthen argument and the gap-diagnosis protocol transfer cleanly from the classic GMAT to the GMAT Focus, because the underlying Critical Reasoning skill has not changed. What has changed is the pacing pressure and the distractor quality in the upper difficulty pool. Candidates who prepared on the classic GMAT should still drill the protocol against GMAT Focus items, because the adaptive format changes which distractors appear and how often the supportive-sound fallacy is engineered to fire. A diagnostic assessment is the cleanest way to confirm that the protocol is producing the expected accuracy against the new item pool.

What does a GMAT Focus Strengthen stem actually ask you to defend