Why infer? The use and misuse of population data in sport research

While the use of inferential statistics is a nearly universal practice in the social sciences, there are instances where its application is unnecessary or, worse, misleading. This is true for most research on the Relative Age Effect (RAE) in sports. Given the limited amount of data needed to examine RAE (birth dates) and the availability of complete team rosters, RAE researchers are in a unique position— inference is not needed when interpreting findings because the data is from a population. We reveal, over the course of five years, the misapplication of inferential statistics using census data in 10 of 13 RAE studies across 12 sports journals. Thus, perhaps by inertia, the majority of RAE researchers use inferential statistics with their census data, misusing analytic techniques and, in some cases, undervaluing meaningful patterns and trends.