Toward a knowledge base for school learning

The purpose of this article is to identify and estimate the influence of educa-tional, psychological, and social factors on learning. Using evidence accumu-lated from 61 research experts, 91 meta-analyses, and 179 handbook chap-ters and narrative reviews, the data for analysis represent over 11,000 relationships. Three methods—content analyses, expert ratings, and results from meta-analyses—are used to quantify the importance and consistency of variables that influence learning. Regardless of which method is employed, there is moderate to substantial agreement on the categories exerting the greatest influence on school learning as well as those that have less influence. The results suggest an emergent knowledge base for school learning. Gener-ally, proximal variables (e.g., psychological, instructional, and home envi-ronment) exert more influence than distal variables (e.g., demographic, policy, and organizational). The robustness and consistency of the findings suggest they can be used to inform educational policies and practices. During the 1980s, two developments occurred that altered the way educator