Degrees of Freedom in SEM: Are We Testing the Models That We Claim to Test?

Structural equation modeling (SEM) has been a staple of the organizational sciences for decades. It is common to report degrees of freedom (df) for tested models, and it should be possible for a reader to recreate df for any model in a published paper. We reviewed 784 models from 75 papers published in top journals in order to understand df-related reporting practices and discover how often reported df matched those that we computed based on the information given in the papers. Among other things, we found that both df and the information necessary to compute them were available about three-quarters of the time. We also found that computed df matched reported df only 62% of the time. Discrepancies were particularly common in structural (as opposed to measurement) models and were often large in magnitude. This means that the models for which fit indices are offered are often different from those described in published papers. Finally, we offer an online tool for computing df and recommendations, the Degrees of Freedom Reporting Standards (DFRS), for authors, reviewers, and editors.