Intra-individual Variability

A standard assumption of multilevel models is that the residual variance is the same for all individuals. However, it is a well-known finding that individuals differ in the amount they vary. For instance, some narcissists tend to vary strongly in state self-esteem. This project is devoted to the development of new methods to model such individual differences in intra-individual variability. This involves the derivation of maximum likelihood or Bayesian estimators, the implementation of these estimators in open source software, and the examination of the statistical properties of these estimators.

Representative publications:

Nestler, S. (2021). Modeling intraindividual variability in growth with measurement burst designs. Structural Equation Modeling: A Multidisciplinary Journal, 28, 28-39.

Nestler, S. (2020). Modeling interindividual differences in latent within-person variation: The confirmatory factor level variability model. British Journal of Mathematical and Statistical Psychology, 73, 452-473.

Nestler, S. & Humberg, S. (2022). A Lasso and a regression tree mixed-effect model with random effects for the level, the residual variance, and the autocorrelation. Psychometrika, 87, 506-532.