The Policy Studies Institute is a British think-tank. It was formed in 1978 through the merger of the former Centre for Studies in Social Policy (est 1972) and Political and Economic Planning (est 1931). Since 1998 it has been an independent subsidiary of the University of Westminster. In 2009 PSI merged with the University of Westminster, and it is expected it will cease to operate as a separate charity. The current director of PSI is Malcolm Rigg.
The Institute presently undertakes qualitative and quantitative research in two broad areas: work and social policy, and the environment. The Institute is also a partner in a number of initiatives with other bodies, including the Green Fiscal Commission. PSI launched two journals, Cultural Trends and Policy Studies, both of which are now published by Taylor & Francis. PSI takes a politically neutral stance on issues of public policy and has no connections with any political party, commercial interest or pressure group. Some of their past publications have been archived on their website.