Mediation analysis is an important statistical tool in many research fields, where the joint significance test is widely utilized for examining mediation effects. Nevertheless, the limitation of this mediation testing method stems from its conservative Type I error, which reduces its statistical power and imposes certain constraints on its…

Ten articles on the use of multilevel data in educational research are presented. Topics include model specification and building, analytical procedures, aggregation bias, least squares statistics, hierarchical linear models, significance testing, and testing multilevel product-process networks. (TJH)