A primer on fixed-effects and fixed-effects panel modeling using R, Stata, and SPSS

Read the full article See related articles

Listed in

This article is not in any list yet, why not save it to one of your lists.
Log in to save this article

Abstract

Fixed-effects modeling is a powerful tool for estimating within-cluster associations in cross-sectional data and within-participant associations in longitudinal data. Although commonly used by other social scientists, this tool remains largely unknown to psychologists. To address this issue, we offer a pedagogical primer tailored for this audience, complete with R, Stata, and SPSS scripts. This primer is organized into three parts. In PART 1, we show how fixed-effects modeling applies to clustered cross-sectional data. We introduce the concepts of ‘cluster dummies’ and ‘demeaning,’ and provide scripts to estimate the within-school association between sports and depression in a fictional dataset. In PART 2, we show how fixed-effects modeling applies to longitudinal data, and provide scripts to estimate the within-participant association between sports and depression over time in a fictional four-wave dataset. In this part, we cover three additional topics. First, we explain how to calculate effect sizes and offer simulation-based sample size guidelines to detect within-participant effects of plausible magnitude with sufficient power. Second, we show how to test two possible interactions: between a time-invariant and a time-varying predictor, and between two time-varying predictors. Third, we introduce three relevant extensions: first-difference modeling (estimating changes from one wave to the next); time-distributed fixed-effects modeling (estimating changes before, during, and after an individual event); and within-between multilevel modeling (estimating both within- and between-participant associations). In PART 3, we discuss two limitations of fixed-effects modeling: time-varying confounders and reverse causation. We conclude with reflections on causality in nonexperimental data.

Article activity feed