title: An applied examination of different weighting methods for the root expected mean square difference and root mean square difference indices.
abstract: It is possible that functions used to link tests are sensitive to subpopulations of test takers. The REMSD and RMSD(x) are weighted effect sizes of linking invariance, yet it is often unclear how the weights are most appropriately applied when subpopulation group sizes are heterogeneous. The objective of this research is to apply two different weighting methods to the REMSD and RMSD(x) functions while testing for population invariance in a linkage across subpopulations of disparate sample sizes, and to subsequently compare the results across these differentially weighted effect sizes. The findings demonstrate that utilizing proportional weights in the REMSD and RMSD(x) indices can underestimate differences in linking functions for small subpopulations.
authors.affiliation: Research and Evaluation Methodology, School of Human Development and Organizational Studies in Education, University of Florida, 1215 Norman Hall, Gainesville, FL 32611, USA. ahuggins@coe.ufl.edu
authors.forename: Anne Corinne
authors.initials: AC
authors.lastname: Huggins
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004521:Educational Measurement / Q000379:methods*; D016018:Least-Squares Analysis; D015233:Models, Statistical