The major forms of evidence that support a standard's credibility are reviewed, and what can be done over time and for different forms of an examination to enhance its comparability in a credentialing setting is outlined. Pass-fail decisions must be consistent to ensure a standard's credibility. (SLD)

Technical advances of the last 15 years in measurement theory and practice are described, notably criterion-referenced testing, item response theory, and computers and testing. Several remaining problems concerning the development and validation of credentialing examinations are also considered. (Author/LMO)