Meta-Analysis in Education: A Reply to Slavin

rors of interpretation in Slavin's article. Each section was developed by one or more of the authors of the synthesis criticized in Slavin's article. Slavin invokes two old objections to how meta-analysis is used: You can't combine apples and oranges, and You shouldn't perpetuate the results of sloppy research. These have been debated at length in various books and journals, and it is not our intent to rehash this debate. We merely note that the debate long ago resulted in the general use of procedures to test the presence and degree of such problems, that the procedures are described in several sources (notably Glass, McGaw & Smith, 1981; and Smith, Glass & Miller, 1980) and that merely raising the issues once again neither validates them nor successfully convicts meta-analysts of failing to deal with them.