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 ...

The following discussion is based on the framework of Campbell and Stanley, [1] in that specific threats to establishing a cause-and-effect relationship (i.e., internal validity) are associated with ...

Although problems with internal validity are typically associated with studies reporting statistically significant differences, methodological problems may introduce extraneous variance into the study ...