2.2 Evidence & Support

Kinds of evidence

Evidence supports claims: facts, statistics, expert testimony, anecdotes, examples, and analogies. Different audiences and purposes call for different kinds.

Relevance and sufficiency

Good evidence is relevant (directly bears on the claim) and sufficient (enough to convince). A single anecdote rarely proves a broad claim; a pattern of examples is stronger.

Credibility of sources

Evidence is only as strong as its source. Writers weigh a source's reliability — expertise, bias, and recency — and audiences judge arguments partly by the quality of the evidence cited.

Key terms

Evidence

Facts, data, testimony, or examples that support a claim.

Relevance

How directly evidence bears on the claim.

Sufficiency

Whether there is enough evidence to convince.

Source reliability

A source's expertise, bias, and recency.

Anecdote

A single story — vivid but weak as sole proof of a broad claim.

Try an AP-style question

Which evidence is most credible for a claim about public health?

1. A peer-reviewed study
2. An anonymous blog post
3. A single anecdote
4. A celebrity's opinion