The Most Common Trap: "Can't Tell" vs "True"

The single most common error in UCAT Verbal Reasoning is selecting "True" when the correct answer is "Can't Tell." This happens because the statement seems obviously correct — either because it is true in real life, because it is very plausible given the passage, or because it is a tempting inference. This lesson focuses entirely on this specific error, with extensive practice to recalibrate your judgement.

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Why This Error Is So Common

Reason	How It Leads to Error
Prior knowledge	You know the statement is true in the real world, so you assume the passage supports it
Plausible inference	The statement seems to follow logically, but it actually requires an extra assumption
Emotional agreement	You agree with the statement personally, which makes it "feel" true
Speed pressure	Under time pressure, you take shortcuts and skip the verification step
Confirmation bias	You look for evidence supporting the statement and overlook the absence of evidence

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The Recalibration Exercise

For each of the following, your instinct will be "True." The correct answer for every single one is "Can't Tell." Study why.

Example 1

Passage: "The university offers courses in 45 different subjects, including medicine, law, engineering, and the humanities."

Statement: "The university offers a course in physics."

Why it feels True: Physics is a common university subject. If the university has 45 subjects, physics is almost certainly one of them.

Why it is Can't Tell: The passage lists four examples but does not mention physics. We cannot confirm from the passage that physics is offered. It might be, or it might not — we simply cannot tell.

Example 2

Passage: "The new hospital wing was opened by the Health Secretary in March 2023. The wing includes 120 beds and two new operating theatres."

Statement: "The hospital received government funding for the new wing."

Why it feels True: The Health Secretary opened it, so the government was probably involved in funding it.

Why it is Can't Tell: The Health Secretary opening the wing does not mean the government funded it. Politicians open privately funded buildings all the time. The passage says nothing about funding.

Example 3

Passage: "The study found that children who read for at least 30 minutes per day scored significantly higher on comprehension tests than those who read for less than 10 minutes per day."

Statement: "Reading improves children's comprehension."

Why it feels True: Higher reading is associated with better comprehension — seems like proof.

Why it is Can't Tell: The study found a correlation between reading time and comprehension scores. But correlation does not equal causation. Perhaps children who are already good at comprehension enjoy reading more. The passage does not establish causation.

Example 4

Passage: "The company reported its highest ever annual revenue of £450 million in 2022."

Statement: "The company's chief executive was satisfied with the 2022 financial results."

Why it feels True: Highest ever revenue — of course the CEO would be satisfied.

Why it is Can't Tell: The passage says nothing about the CEO's reaction. Revenue is not the same as profit — costs could have risen even more. Even with record revenue, the CEO might have been disappointed if the target was £500 million.

Example 5

Passage: "A survey of 2,000 adults in the UK found that 83% supported mandatory vaccination for healthcare workers."

Statement: "The majority of UK adults support mandatory vaccination for healthcare workers."

Why it feels True: 83% of 2,000 adults is a clear majority.

Why it is Can't Tell: 2,000 adults is a sample. Whether the results are representative of all UK adults depends on sampling methodology, which the passage does not describe. The statement says "the majority of UK adults" — not "the majority of surveyed adults." The generalisation from sample to population is not confirmed by the passage.

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The Pattern: What These All Have in Common

Every example above involves the same logical structure:

1. The passage provides some information
2. The statement adds something that feels natural but is not actually in the passage
3. The added element seems so obvious that candidates assume the passage supports it

Types of "Added Elements"