What Knowledge Base?

"Toward a Knowledge Base for School Learning" (Wang, Haertel, & Walberg, 1993a) is an ambitious and provocative piece of work. It purports to capture the essential lessons from several broad domains of research and translate them into findings that are relevant for educational policy and practice. Its main finding is that so-called distal variables (demography, policy, and organization) have relatively little influence on learning, while so-called proximal variables (individual psychology, classroom instruction, and home environment) have relatively greater influence. I have neither the inclination nor the expertise to criticize the authors' methodology. In general, I find the genre of cross-cutting analyses of existing research—whether they are reviews or meta-analyses—to be enormously interesting and helpful. I find the methodological battles around this genre also to be interesting in small doses and extremely boring in large doses. I am glad that people worry about the methodological issues involved in the aggregation of research results. I understand that it is an important field of scholarly debate. But I must say frankly that I do not form my judgments about "what the research says" on the basis of these methodological disputes. So my comments will not focus on this dimension of the review. My interests lie rather in the relationship among research, policy, and educational practice (defined both as the practice of organizing and operating schools and the practice of designing curriculum and teaching it). From this perspective, I find "Toward a Knowledge Base for School Learning" to be more intriguing for what it doesn't say than for what it does say. The idea of a knowledge base is simply a convenient hook on which the authors hang their findings. Since the idea of a knowledge base is undefined, the findings hang in thin air—suspended in a peculiar world that has more to do with research and researchers than it has to do with anything related to policy or practice. The knowledge base hook, then, is a skyhook. The problems I have with this review are many of the same problems I have with other similar attempts to capture a knowledge base by analyzing existing research on schooling. I find these reviews and meta-analyses often stimulating and useful in thinking about research. I find them practically useless in thinking about policy and practice. Let me explain briefly why this might be so.