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 Massachusetts state Education Department last year commissioned Mathematica Policy Research to do a validity study comparing the Common Core test known as PARCC, created by a federally funded ...

Background Self-report instruments to assess physical activity are still the most feasible option in many population-wide surveys, and often need to be very short owing to resource constraints. The ...

The Grit Scale questionnaire has gained popularity over the past decade, not only in research but also in practical psychology and in employee selection. The questionnaire is used to measure grit—a ...