There is a distinction that one learns about on the first day of a course in psychological research methods. It is the difference between internal and external validity. Internal validity is ...

In everyday language, the term validity is typically used to describe something as being trustworthy or legit. It's meaning in psychology suggests something similar—it's all about whether we can trust ...

The maturation threat can operate when biological or psychological changes occur within subjects and these changes may account in part or in total for effects discerned in the study. For example, a ...