Contemporary research on any important topic tends to be vast, and its findings are often disparate and widely dispersed. This “flood of numbers” threatens to drown economic knowledge and sensible policy action (Heckman, 2001). Yet, without some objective and comprehensive understanding of economics research, informed policy is impossible. 1 Unfortunately, conventional narrative reviews are not up to the task. It is all too easy for conventional reviewers to ignore findings that do not fit into their theories or ideology. Without objective standards, it is a hopeless task to assess what the genuine message of a given conventional review might actually be. Hence, experienced researchers often discount narrative reviews. And yet, there is an indisputable need for research synthesis.