This issue introduces a new framework for thinking about research from the standpoint of usable knowledge. Impact Validity is the extent to which research has the potential to play a role in social and political change or is useful as a tool for advocacy or activism. A series of articles have been collected for this issue that exemplify the intersection of science, activism / advocacy, and social change. These articles highlight the ways in which others have strategically grounded their research in the advocacy needs of the social/political issue they are trying to influence, and the various decisions throughout the research process that have had a bearing on its potential to be useful in addressing social problems. These decisions, which rarely receive systematic attention, take central stage.