Test frequency, stakes associated with educational tests, and feedback from test results have been identified in the research literature as relevant factors in student achievement.Summarize the separate and joint contribution to student achievement of these three treatments and their interactions via multivariable meta-analytic techniques using a database of English-language studies spanning a century (1910-2010), comprising 149 studies and 509 effect size estimates.Analysis employed robust variance estimation. Considered as potential moderators were hundreds of study features comprising various test designs and test administration, demographic, and source document characteristics.Subjects were students at all levels, from early childhood to adult, mostly from the United States but also eight other countries.We find a summary effect size of 0.84 for the three treatments collectively. Further analysis suggests benefits accrue to the incremental addition of combinations of testing and feedback or stakes and feedback. Moderator analysis shows higher effect sizes associated with the following study characteristics: more recent year of publication, summative (rather than formative) testing, constructed (rather than selected) item response formats, alignment of subject matter between pre- and posttests, and recognition/recall (rather than core subjects, art, or physical education). Conversely, lower effect sizes are associated with postsecondary students (rather than early childhood-upper secondary), special education population, larger study population, random assignment (rather than another sampling method), use of shadow test as outcome measure, designation of individuals (rather than groups) as units of analysis, and academic (rather than corporate or government) research.