Terrence Jorgensen is an assistant professor of methods and statistics within the Department of Child Development and Education at the University of Amsterdam. His areas of expertise span structural equation modeling (SEM), multilevel modeling (MLM), social-relations modeling (SRM), and their intersections (i.e., ML-SEM and the SR-SEM), as well as nonparametric methods, Bayesian inference, and modern missing data methods. His methodological research interests involve statistical programming for psychometric methods. He is a coauthor of the R package lavaan and develops key software in the "lavaan ecosystem" (e.g., as primary developer of the R package semTools maintainer of the R package simsem, and contributor to the R package blavaan). The semTools package includes a variety of methods extending lavaan's capabilities, such as evaluating reliability, testing measurement equivalence / invariance (particularly in the case of ordinal indicators: item factor analysis), and applying modern missing-data methods to SEM (e.g., multiple imputation, two-stage MLE, and adding auxiliary covariates to justify FIML's MAR assumption). His most recent focus is the application of SEM to round-robin data (networks of dyadic observations).