The Fixed Versus Random Effects Debate and How It Relates to Centering in Multilevel Modeling
The Fixed Versus Random Effects Debate and How It Relates to Centering in Multilevel Modeling
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DOI:
10.1037/met0000239
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发表时间:
2020-06-01
影响因子:
7
通讯作者:
Muthen, Bengt
中科院分区:
文献类型:
--
作者:
Hamaker, Ellen L.;Muthen, Bengt
In many disciplines researchers use longitudinal panel data to investigate the potentially causal relationship between 2 variables. However, the conventions and concerns vary widely across disciplines. Here we focus on 2 concerns, that is: (a) the concern about random effects versus fixed effects, which is central in the (micro)econometrics/sociology literature; and (b) the concern about grand mean versus group (or person) mean centering, which is central in the multilevel literature associated with disciplines like psychology and educational sciences. We show that these 2 concerns are actually addressing the same underlying issue. We discuss diverse modeling methods based on either multilevel regression modeling with the data in long format, or structural equation modeling with the data in wide format, and compare these approaches with simulated data. We extend the multilevel model with random slopes and discuss the consequences of this. Subsequently, we provide guidelines on how to choose between the diverse modeling options. We illustrate the use of these guidelines with an empirical example based on intensive longitudinal data, in which we consider both a time-varying and a time-invariant covariate.Translational AbstractWhen it comes to the gold standard for modeling particular data, there can be stark differences across disciplines. In this article we discuss one such difference between psychology on the one hand, and disciplines like (micro)econometrics, sociology, and political sciences on the other. Specifically, our focus is on how to handle longitudinal data, which consists of repeated measurements of the same cases (e.g., individuals, couples, families, or companies), when the interest is in how one variable predicts-or even causes-another variable. We show that the concerns that are raised in these disciplines seem quite distinct, but are in fact identical. We show this analytically and through simulations, and provide guidelines for researchers to help them decide which modeling approach to use in practice.