Historical institutionalism (HI) is a new institutionalist social science approach that emphasizes how timing, sequences and path dependence affect institutions, and shape social, political, economic behavior and change. Unlike functionalist theories and some rational choice approaches, historical institutionalism tends to emphasize that many outcomes are possible, small events and flukes can have large consequences, actions are hard to reverse once they take place, and that outcomes may be inefficient. A critical juncture may set in motion events that are hard to reverse, because of issues related to path dependency. Historical institutionalists tend to focus on history (longer temporal horizons) to understand why specific events happen.
The term "Historical Institutionalism" began appearing in publications in the early 1990s, although it had been used in the late 1980s. The most widely cited historical institutionalist scholars are Peter Hall, Paul Pierson, Theda Skocpol, Douglass North, and Kathleen Thelen. Prominent works of historical institutionalist scholarship have used both sociological and rationalist methods. Due to a focus on events involving causal complexity (equifinality, complex interaction effects and path dependency), historical institutionalist works tend to employ detailed comparative case studies.
