Glossary
assumption
An assumption is the belief a claim needs in order to work, and that the passage usually leaves unstated — the missing step between the evidence and the conclusion.
Assumption is the belief a claim needs in order to hold and that the passage usually leaves unstated. A survey mailed to drivers is offered as a guide to a whole downtown, and the step that lets the finding mean that is missing: that the people who answered speak for everyone. Because the step is usually not written down, it is not quoted in the passage, and that is what makes the item answerable. The method is to read the claim, ask what must also be true for it to follow, and answer in a sentence the passage does not contain. A premise is sometimes printed in the passage instead; then the question asks how the conclusion depends on that printed sentence, and the answer says what it would take for the conclusion to fail. Two wrong choices dominate. One restates the passage's own figures, which is the evidence rather than the belief under it. The other is a belief that is reasonable but that the argument does not use. A second question shape runs the same relationship backwards — which finding, if it were true, would weaken the claim — and the answer is the finding that would break the missing step.
Taught in
Related terms
- bias — Bias is a leaning a passage does not admit: what it counts, what it leaves out, and whose voice it never reports.
- fact and opinion — A stated fact is something a reader could check against a record; an opinion is a judgment, a recommendation, or the writer's own unverifiable claim about what someone else knows or intends.
Source: The reading skills ATI names in its own Content Outline (R.2.1-R.2.4, under the Craft and structure sub-content area), plus the tone and passage-structure skills that sub-content area's published description names; each definition below is written for the Craft and Structure guide in this exam, in our own words, and explains the skill the way the guide teaches it. (ATI Content Outline read 2026-10-09; definitions written 2026-10-09)