Does the Support Fit the Thesis?

Evaluate whether an argument's evidence and reasoning actually support its central claim.

Identifying a thesis is the beginning; evaluating it means checking whether the support truly fits. Three questions are useful. Is the evidence relevant, actually bearing on the claim? Is it sufficient, enough to justify the claim's scope? Is the reasoning sound, so that the conclusion follows from the evidence? Consider an original argument: 'The school should adopt a later start time. Last month, three students told me they feel tired in first period, and a famous athlete once said sleep is the secret to success.

' The evidence is relevant only loosely, insufficient (three students), and partly irrelevant (an athlete's quote is not evidence about school schedules). The thesis may be reasonable, but this support does not establish it. Compare: 'A multi-district study found that students at later-starting schools slept more and had better attendance. ' That is relevant, broader, and connected to the claim. Remember that weak support does not prove a thesis false; it shows the argument has not earned it.

• 1Check evidence for relevance and sufficiency.
• 2Check that reasoning connects evidence to claim.
• 3Weak support does not prove a thesis false.