An alternative definition has been developed of the delta scale of item difficulty used at Educational Testing Service. The traditional delta scale uses an inverse normal transformation based on normal ogive models developed years ago. However, no use is made of this fact in typical uses of item deltas. It is simply one way to make the probability…

Psychometric theory has been one of psychology's stronger foundations and a major contributor to the recognition of psychology as a scientific discipline. Basic principles of psychometric theory led to the development of respected intelligence tests and large and comprehensive testing and assessment programs. This paper synthesizes major…

The sequential probability ratio test (SPRT), developed by Abraham Wald, is one statistical model available for making mastery decisions during computer-based criterion referenced tests. The predictive validity of the SPRT was empirically investigated with two different and relatively large item pools with heterogeneous item parameters. Graduate…