a1 Carnegie Mellon University email@example.com
This article considers the question ‘How should institutions enable people to meet their needs in situations where there is no guarantee that all needs can be met?’ After considering and rejecting several simple principles for meeting needs, it suggests a new effectiveness principle that (1) gives greater weight to the needs of the less well off and (2) gives weight to enabling a greater number of people to meet their needs. The effectiveness principle has some advantage over the main competitors including a principle suggested by David Miller in Principles of Social Justice. Miller argues that his principle accounts for the existing data on individuals' intuitions about meeting needs. The effectiveness principle better accounts for this data. Furthermore, this article presents a new experiment on intuitions about meeting need that is consistent with the effectiveness principle but not Miller's principle.