Standardized Mean Difference Effect Sizes in Two-Level Models

• In Event: Poster Session 10
  In Poster Session: Multilevel Modeling: Complex Survey Data and Effect Size

Abstract

Using ELS:2002 data (Education Longitudinal Survey) we will provide illustrations and discussion on the different ways to calculate and report effect sizes in the context of a two-level model, namely, variance-accounted-for effect sizes, and standardized mean difference effect sizes. We will give special emphasis to the later, especially since empirical evidence points at a big difference in the magnitude of the effect size when using the standard deviation of the outcome of interest versus the standard deviation of the outcome as estimated by the between-group variance of a two-level empty model. Confidence intervals in the context of effect sizes will also be discussed.

Author

• Gloria Yeomans-Maldonado, The Ohio State University - Columbus