Marie Wiberg is professor of statistics with a specialty in psychometrics at Umeå University, Sweden. Her research interests include test equating, applied statistics, large-scale assessments and psychometrics in general. Dylan Molenaar is assistant professor at the department of psychology, University of Amsterdam, the Netherlands. His research interests include item response theory, factor analysis, response time modeling, mixture modeling, modeling of intelligence test data, and modeling of genotype by environmental interactions. Jorge González is associate professor at the department of statistics, Pontificia Universidad Católica de Chile. His research interests include statistical modeling of social sciences data, particularly in the fields of educational measurement and psychometrics. Jee-Seon Kim is professor in the department of educational psychology at the University of Wisconsin–Madison. Her research interests include multilevel and hierarchical modeling, longitudinal data analysis, latent variable modeling, and causal inference with clustered observational data. Heungsun Hwang is professor in the department of psychology at McGill University. His research interests include multivariate statistics, machine learning, functional data analysis, and genetic and neuroimaging data analysis.