Many researchers and research funders want their work to be influential in educational policy and practice, but there is little systematic understanding of how policymakers and practitioners use research evidence, much less how they acquire or interpret it. By understanding what does shape policymakers' and practitioners' decision making and the role of research evidence in those decisions, the research community may be able to improve the likelihood that their work will be used to directly inform policy and practice. This study sought to contribute to that goal by helping to identify when, how, and under what conditions research evidence is used by policymakers and practitioners; what other sources of information these individuals rely on; and what factors serve as barriers or facilitators to using research evidence in making policy and practice decisions. In shedding light on those topics, the authors hoped to uncover promising areas for future investigation by researchers. The study was conducted in fall 2008 through spring 2009 by the Northwest Regional Educational Laboratory, in collaboration with the Center for Knowledge Use in Education and with the support of the William T. Grant Foundation. The research team used a combination of structured focus groups and individual interviews to elicit comments from a limited, self-selected sample of 65 influential leaders in the areas of policy and practice. Participants represented six groups of federal, state, and local educational interests. The authors' findings suggest that barriers to the use of research evidence are linked to an underlying belief that much research is not to be trusted or is, at least, severely limited in its potential applicability. Even with studies that meet "gold standard" criteria, participants were aware that a narrowly designed study could report a false success or a false failure. It was a common perception of the study participants that research could be shaped to say anything, that one piece of research often conflicts with another, and that much research is not timely for users' needs. Three appendixes are included: (1) Summary of Group Demographics; (2) Focus Group Questioning Guides; and (3) Sources of Evidence Cited by Participants. (Contains 1 table.)