Using Fit Indexes to Select a Covariance Model for Longitudinal Data

Siwei Liu, Michael J. Rovine, Peter C.M. Molenaar

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


This study investigated the performance of fit indexes in selecting a covariance structure for longitudinal data. Data were simulated to follow a compound symmetry, first-order autoregressive, first-order moving average, or random-coefficients covariance structure. We examined the ability of the likelihood ratio test (LRT), root mean square error of approximation (RMSEA), comparative fit index (CFI), and Tucker-Lewis Index (TLI) to reject misspecified models with varying degrees of misspecification. With a sample size of 20, RMSEA, CFI, and TLI are high in both Type I and Type II error rates, whereas LRT has a high Type II error rate. With a sample size of 100, these indexes generally have satisfactory performance, but CFI and TLI are affected by a confounding effect of their baseline model. Akaike's Information Criterion (AIC) and Bayesian Information Criterion (BIC) have high success rates in identifying the true model when sample size is 100. A comparison with the mixed model approach indicates that separately modeling the means and covariance structures in structural equation modeling dramatically improves the success rate of AIC and BIC.

Original languageEnglish (US)
Pages (from-to)633-650
Number of pages18
JournalStructural Equation Modeling
Issue number4
StatePublished - Oct 1 2012

All Science Journal Classification (ASJC) codes

  • General Decision Sciences
  • Modeling and Simulation
  • Sociology and Political Science
  • Economics, Econometrics and Finance(all)


Dive into the research topics of 'Using Fit Indexes to Select a Covariance Model for Longitudinal Data'. Together they form a unique fingerprint.

Cite this