Using results of a best-evidence synthesis and a meta-analysis of an extensive international database, it is argued that there is no empirical evidence at the moment showing that student learning suffers in combination classes. No support is found for the selection bias suggested by D. Mason and R. Burns (1997). (SLD)

S. Veenman argues that his reviews of the literature lead to the conclusion that combination classes are neither worse nor better than single-grade classes. This rejoinder discusses disagreements with Veenman's findings, which are hampered by a narrow reading and interpretation of the literature on potential positive effects of combination…

Research on combination classes, in which students from two or more grades are placed with one teacher for most or all of the school day, is reviewed. Consistent research findings are that combination classes, distinguished from multiage/nongraded classes, have at least a small negative effect on student achievement. (SLD)