The study explores the relative effects of a wide range of variables that influence learning, and whether three methods--content analysis, expert ratings, and meta-analysis--agree on whether and how strongly these variables influence learning, using the educational research literature and an expert survey. The presence of an emergent knowledge base for school learning was also investigated. A framework was developed to guide the study that incorporated the following theoretical constructs: (1) state and district governance and organization; (2) home and community educational contexts; (3) school demographics, culture, climate, policies, and practices; (4) design and delivery of curriculum and instruction; (5) classroom practices; and (6) student characteristics. Data from 179 handbook chapters (narrative reviews) were used for the content analysis, and a survey of 61 educational researchers provided expert ratings. Meta-analysis was conducted with 91 studies. The magnitude of the correlation between the meta-analyses and the narrative reviews suggests an emergent knowledge base on school learning. The moderate correlation of expert ratings with the results from meta-analysis and narrative reviews also supports an emergent knowledge base on influences on learning. Three appendixes provide technical information on the narrative reviews and expert survey and a list of the 91 sources used in the meta-analysis. (Contains 1 figure, 4 tables, and 119 references.) (SLD)