AP® English Language and Composition · Big Idea 2
3.A Types of Evidence (CLE-1.C)
Evidence comes in different kinds—facts, statistics, anecdotes, analogies, and testimony—and each one answers a different kind of doubt, so strong writing matches the evidence type to the specific question a skeptical reader is actually asking.
A claim invites doubt, and different doubts need different proof. A reader might doubt that something happened at all, that it happens often or widely, that it matters to the people involved, or that someone qualified actually believes it. Facts settle whether something happened. Statistics settle how widespread or sizable a pattern is. Anecdotes and analogies make an abstract pattern felt by putting a face or a familiar comparison on it. Testimony and expert opinion settle whether someone with standing to judge backs the claim. Picking the wrong type doesn't just weaken an argument, it leaves the actual doubt untouched, no matter how much of that evidence piles up.
This is why a number lands differently than a story even when they support the same claim. A statistic like '18 percent higher error rate across 4,000 nurses' answers a doubt about scale or pattern across a population. A story about one nurse's exhausting double shift answers a doubt about what that pattern feels like up close. Neither replaces the other, because they're built to close different gaps in a reader's trust.
This sets up the next move in an argument: commentary, the sentences that explain why the evidence actually proves the claim. Evidence alone just sits there. A writer has to name the doubt the evidence targets and then show, in their own words, how closing that doubt supports the larger point. Matching evidence to doubt is the selection step; commentary is the welding step that makes the match visible to the reader.
Key terms
- Statistical evidence
- Numerical data showing a pattern, rate, or trend across a group, used to answer doubts about scale or frequency.
- Anecdotal evidence
- A specific story or example about one person or event, used to make a pattern concrete and felt.
- Testimony
- A firsthand account from someone involved, used to answer doubts about lived experience or credibility.
- Expert opinion
- A judgment from someone with recognized authority in a field, used to answer doubts about whether qualified people agree.
- Commentary
- The writer's own sentences explaining why a piece of evidence actually supports the claim.
Watch it explained
- How it worksHow do facts, statistics, anecdotes, analogies, testimony and expert opinion each carry weight differently?
- How it worksWalk me through matching four evidence types to the four kinds of doubt a skeptical reader arrives with.
- Worked exampleFind the evidence type in 'A 2019 study of 4,000 nurses found shift work raised error rates by 18 percent'.
- Common mistakeWhy isn't a bigger pile of evidence automatically stronger support for a claim?
Check yourself
End of topic.