Kathryn Snow does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their ...

On watching this video, students should be able to: Distinguish between an observational and experimental study. Explain the main reason why a randomised experiment can if done well, be used as a test ...

A natural experiment is an empirical study in which individuals (or clusters of individuals) are exposed to the experimental and control conditions that are determined by nature or by other factors ...