CGSSM: Stata module implementing the contrasting groups' standard setting method

Establishing a competency standard for when a certain level of expertise is reached by identifying cut-off points on different performance measures based on rating scores or simulator metrics is an important issue in competency-based learning. One method to set such standards, is the contrasting groups' standard setting method. It is a participant-based method where the performance of a certain procedure is evaluated between participants of different expertise level, e.g., novices and experts. Using the contrasting groups' method, the cut-off point is set by identifying the intercept of two normally distributed curves that represent the score distributions of the groups defined by their level of expertise. After a pass/fail score is defined, the percentage of false positives and negatives can be calculated to explore the consequences of the test. Traditionally, these false positives and false negatives are calculated based on the observed number of individuals who passes or fails a test. However, validity studies often include only a small number of participants. These small numbers make the rate of false positives and false negatives sensitive to outliers. Instead, using the normally distributed curves that represent the score distributions of the groups defined by their level of expertise, the theoretical false negatives, and theoretical false positives can be calculated. What is new in cgssm and cgssmi is that the cut-off is found using an exact formula based on solving a polynomial of first or second order degree.