The Campbell and Cochrane Collaborations were created to reveal the evidentiary status of claims focusing especially on the effectiveness of specific interventions. Such reviews are constrained by the population of studies available and biases that may influence this availability such as preferred framing of problems. This highlights the importance of attending to how problems are framed and the validity of measures used in such reviews, as well as the importance of reviews focusing on questions concerning problem framing and the accuracy of measures. Neglecting such questions, both within reviews of effectiveness and in separate reviews concerning related claims, results in lost opportunities to decrease avoidable ignorance. Domains of avoidable ignorance are suggested using examples of Cochrane/Campbell reviews. Without attention to problem framing, systematic reviews may contribute to maintaining avoidable ignorance.
Due to evidence linking education and development, funding has been invested in interventions relevant to getting youth into school and keeping them there. This article reports on a systematic review of impact studies of these school enrollment interventions. Reports were identified through electronic searches of bibliographic databases and other methods. To be eligible, studies (1) assessed impact on primary or secondary school enrollment outcomes; (2) used a rigorous design; (3) were conducted in a low- or middle-income nation; (4) included at least one quantifiable measure of enrollment or related outcomes; (5) were available before December 2009; and (6) included data on participants post-1990. A coding instrument extracted data on study characteristics from each report. Standardized mean difference effect sizes were computed for the first effect reported. The sample includes 73 evaluations. The average effect size was positive across all outcomes. However, the results varied. Studies that focused on building new schools and other infrastructure interventions reported the largest average effects.