I will review the way psychometrics has addressed reliability of measurement through the years, and notice that with respect to reliability psychometrics has great difficulty to sail a straight course. The topics I briefly discuss are:
- Definition of reliability through the years
- Methods of estimating reliability
- Different kinds of reliability
- Reliability in different statistical models
- Does knowledge development sail a straight course?
- What do consumers of reliability need?
I will draw a conclusion of where we are with respect to reliability and provide recommendations for future research.