Still Comparing Apples With Oranges?

Measurement invariance testing has become an integral part of the methodological repertoire in psychological assessment. Whenever researchers attempt to compare scales or test scores across groups or over time, it needs to be ensured that they do not compare "apples with oranges." Measurement invariance testing is the road that leads to the information about whether the comparisons of means or variances are valid. In other words, invariance testing examines the between-group or between-time points variation in factor means and variances by ruling out differences in measurement This ensures the fairness of scales or tests and therefore contributes to crafting a validity argument