The validity of reliability assessments.

This paper focuses on reliability and evaluation of health education programs in school settings. Reliability is a concept that guides researchers in selecting or developing instruments, and is used as a standard, with validity and acceptability, for judging the credibility of research findings and inferences. Reliability is defined within the context of research design, and methods for estimating the reliability of cognitive measures are reviewed. Using data gathered in a school health education curriculum evaluation as an example, possible errors in hypotheses testing that may occur when estimating internal consistency of cognitive test scores obtained in quasi-experimental designs are examined. The appropriateness of internal consistency as a measure of reliability of cognitive measures is discussed and suggestions for reliability assessment and related issues such as power analysis are presented.