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 ...

Study design: Measurement evaluation of the external and structural components of validity. Objectives: To examine the relationships between quality of life (QOL) as measured by the spinal cord injury ...

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 ...