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 ...

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 ...

Experiments show significant demobilizing and alienating effects of negative advertising. Although internally valid, experiments may have limited external validity. Aggregate and survey data offer two ...

The cognitive map presented offers a guide to addressing specific problems with the internal validity of experimental studies. This guide will help investigators structure the information required to ...