University of Pennsylvania
Studies that have a significant impact on society tend to be characterized either by particular methodological strengths or by the significance of the question and the broader approach.
The studies that have the most impact are typically characterized by:
well-designed research using rigorous methods, such as randomized controlled trials for large-scale studies or (in the case of more philosophical work) rigorous yet accessible analytical and/or synthetic reasoning;
combination of research methods necessary to address several dimensions of the complexity of the problem (important since every important educational problem is complex);
excellent dissemination, usually with the professional support of a relevant organization.
The most important studies ask broad rather than narrow questions and look at impact beyond the boundaries of the classroom, since education policy and practice must last beyond the classroom (or immediate test results) to be meaningful.
Five examples of (relatively) High Impact Research:
Class size experiments
Perry Preschool Project and Headstart Longitudinal Studies
21st century learning center (government) evaluation of after school programs
Rigorous empirical studies of affirmative action (Bowen-Bok book) and rigorous philosophical (and legal) arguments on affirmative action (Dworkin)
Rigorous and accessible philosophical (and legal) arguments on importance (or lack thereof) of civic education, vouchers, and other ongoing issues that frame public policy debates for decades.