History matters for understanding knowledge exchange.

The narrative systematic review of 205 publications on the “relations between knowledge and action” in this issue concludes that “externally valid evidence about the efficacy of specific knowledge exchange strategies is unlikely to be forthcoming” because “collective knowledge exchange and use are. . . deeply embedded in organizational, policy, and institutional contexts” (Contandriopoulos et al. 2010, 468). The authors’ pessimism about obtaining “externally valid evidence” is the result of a search strategy that largely ignored publications based on historical methods. Accordingly, the theme of my commentary is that historical research provides evidence that sustains cautious generalizations about effective strategies for exchanges between researchers and policymakers in comparable policy and institutional contexts. A definition of exchange informed by history would emphasize reciprocity, that is, how researchers and policymakers have learned from each other. Instead, however, Contandriopoulos and colleagues follow the authors of many of the publications they review in defining exchange, explicitly or implicitly, as the influence on policy of research conducted by full-time knowledge workers. The historical literature, in contrast, describes exchanges in which researchers had a broader array of relationships with policy; advising policymakers in person and in writing, working as members of their staff, and serving as policymakers themselves. Knowledge derived from both research and political experience has been vital to these exchanges (defining politics here as who, in