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 ...

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 ...

When investigators think of generalizability, they typically think of extrapolating the results to other patient populations, depending on whether patients were selected for the study by means of ...