RT Journal A1 Cook DA, Montori VM, Levinson AJ T1 INternet-based education for health professionals—reply JF JAMA JO JAMA YR 2009 FD February 11 VO 301 IS 6 SP 598 OP 600 DO 10.1001/jama.2009.71 UL http://dx.doi.org/10.1001/jama.2009.71 AB In Reply: Dr Wong notes the limitations of quantitative syntheses in education, inasmuch as the study designs, interventions, participants, institutional contexts, and outcomes all represent sources of heterogeneity. These reviews, therefore, often fail to permit strong causal inferences. Realist reviews1 and other systematic efforts to summarize disparate sources of evidence will provide important insights beyond a pooled estimate. We think, however, that such heterogeneity need not remain the norm in the future. On the contrary, as researchers work collaboratively using common theoretical frameworks, intervention definitions, and outcomes, we expect evidence will accrue that can be systematically synthesized to illuminate practice and advance theory.