Although content validity--how well each item of an instrument represents the construct being measured--is foundational in the development of an instrument, statistical validity is also important to the decisions that are made based on the instrument. The primary purpose of this study is to demonstrate how simulation studies can be used to assist…

This study evaluated the use of bivariate matching as a solution to the problem of studying differential item functioning (DIF) with formula scored tests. Using Scholastic Aptitude Test verbal data with large samples, both male/female and black/white group comparisons were investigated. Mantel-Haenszel (MH) delta-(D) DIF values and DIF category…

In most reliability studies, the precision of a reliability estimate varies inversely with the number of examinees (sample size). Thus, to achieve a given level of accuracy, some minimum sample size is required. An approximation for this minimum size may be made if some reasonable assumptions regarding the mean and standard deviation of the test…