Measuring up: the significance of measurement invariance in cardiovascular research.

Cardiovascular research frequently involves comparing patient-reported outcomes across groups. These groups can include individuals from different countries or those have different cardiovascular conditions, and it is frequently assumed that their understanding of the assessed outcome is similar. However, to ascertain that this is indeed the case, measurement invariance needs to be evaluated. This psychometric property helps us understand whether a test measures the same underlying construct in the same way across different groups. In the absence of measurement invariance, conclusions regarding group comparisons of the construct at hand may be inappropriate. This Methods Corner paper provides an overview of measurement invariance and an example of how it can be evaluated.