We compared coefficient alpha with five alternatives (omega total, omega RT, omega h, GLB, and coefficient H) in two simulation studies. Results showed for unidimensional scales, (a) all indices except omega h performed similarly well for most conditions; (b) alpha is still good; (c) GLB and coefficient H overestimated reliability with small…

Differential item functioning (DIF) analyses are used to identify items that operate differently between two groups, after controlling for ability. The Simultaneous Item Bias Test (SIBTEST) is a popular DIF detection method that matches examinees on a true score estimate of ability. However in some testing situations, like test translation and…

This paper discusses how to determine whether a test was developed in a legally defensible manner, reviewing general issues, specific cases bearing on different types of test use, some evaluative dimensions, and evidence of test quality. Tests constructed and used according to existing standards will generally stand legal scrutiny. (SLD)