The statistical method "meta-analysis" is perhaps unique as a contribution to empirical inquiry of many types because it arose entirely within the practice of education research. In spite of its origins, meta-analysis has found its widest application and most important contributions in the field of medicine. Contrasting the success of meta-analysis in medicine and education reveals interesting lessons for the future of education research. The findings of research studies in education are highly variable. Context matters in very significant ways when studying education phenomena, and decades of research have produced little understanding of these contextual influences. The findings of education studies remain varied in unaccountable ways.