AbstractProviding some form of mediation between academic scientists and social groups that cannot pay for research is not only a matter of social service; it can also be applied as a form of science policy. An evaluation of 162 cases at the University of Amsterdam shows that investigations undertaken on behalf of clients of the local science shop have given rise to follow-up research, publications, and many other enduring effects on academic practice. An analysis of the relevant circumstances of these investigations reveals an interaction among institutional, motivational, and cognitive parameters of the impacts of the social demands on scientific knowledge.