Do not use inferential statistics to evaluate quality of matching

Quantitative research in bilingualism often requires matching between groups on one or more potentially confounding variables. A common approach to assessing the quality of matching is to apply inferential statistics on the variable(s). In this Opinion, I argue that this approach is theoretically and practically problematic, and that there is no purely quantitative, objective alternative. Matching quality can only be evaluated by a comparison of the sample distributions, informed by expert knowledge on the topic of research.