Historical institutionalism

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.

Source: Wikipedia — Historical institutionalism (CC BY-SA 4.0)