>You've picked 30 people who died after eating at the grocery store's salad bar, and used that as evidence that the salad bar is dangerous, without checking how

>You've picked 30 people who died after eating at the grocery store's salad bar, and used that as evidence that the salad bar is dangerous, without checking how many skipped the salad bar and died anyways. The answer to this question would also be socially and politically relevant and warrant its own study. But that doesn't make the author's study unsound or unable to serve as evidence, like you said.