Test equating: What, why, how?

The purpose of this paper is to introduce test equating, including its concept, needs, and methods, to the field of physical education and exercise science. Both traditional and item response theory (IRT) equating methods, along with data collection designs, were described in detail, and the advantages and disadvantages of these methods were also introduced. In addition, equating errors and evaluation criteria, sample size, and related computer programs were introduced. Using an existing data set of sit-up tests, a test-equating application was illustrated through a step-by-step example. As a result, two sit-up tests were equated onto a common scale, and equating accuracy was evaluated using both equating and cross-validation samples. Finally, benefits and potential applications of test equating in assessing motor functions and skills, as well as future research challenges, were described.