How Many Factors to Retain in Exploratory Factor Analysis? A Critical Overview of Factor Retention Methods

Determining the number of factors is a decisive, yet very difficult decision a researcher faces when conducting an exploratory factor analysis (EFA). Over the last decades, numerous so-called factor retention criteria have been developed to infer the latent dimensionality from empirical data. While some tutorials and review articles on EFA exist which give recommendations on how to determine the number of latent factors, there is no comprehensive overview that categorizes the existing approaches and integrates the results of existing simulation studies evaluating the various methods in different data conditions. With this article, we want to provide such an overview enabling (applied) researchers to make an informed decision when choosing a factor retention criterion. Summarizing the most important results from recent simulation studies, we provide guidance when to rely on which method and call for a more thoughtful handling of overly simple heuristics.