This case study is based on a research project the first author conducted for his master’s thesis under the guidance and supervision of the second author, his academic adviser. In this case study, we highlight some of the most important aspects of the project. Specifically, we explain how our research was prompted by the lack of empirical testing of the assumption of measurement invariance in applied research. In turn, the presentation of our research needed to be didactic in nature to serve as a model other researchers could follow. This need to be didactic directed our style of writing in addition to the contents of the published article.
In this case study, we shed light on how we communicated the necessity of assessing the often ignored assumption of measurement invariance when comparing scores from two time points. We explain how we demonstrated the importance of distinguishing “true” change on a construct over time from change in the measurement of the construct between two time points. Next, we present the step-by-step process we found most useful to assess measurement invariance and examine actual change on a construct. We tie this process to the longitudinal mean and covariance structures (LMACS) analysis framework. Finally, we offer several strategies we employed to identify and interpret partial noninvariance. Discussion questions and further readings are provided.