The information needed to determine the internal and external validity of an experimental study is discussed. Internal validity is the degree to which a study establishes the cause-and-effect ...

Internal validity Assess internal validity ... due to the effects of confounding factors or bias; stop here. 3. External validity Examine inclusion and exclusion criteria and characteristics ...

This important research addresses the effects of subjective control and task difficulty on experienced stress using a novel behavioral task in two, large online samples. Convincing evidence is ...