Consistency and Commitment in the Realisation of Extended Plans

This paper is concerned with the problems arising from the changing temporal perspective that accompanies the execution of extended plans. In particular it raises the question of the intertemporal consistency of a sequence of decisions, each consisting of the implementation of the early stages of an extended plan, when the passage of time leaves the underlying objective of the decisionmaker unchanged but nevertheless leads to revisions of the plans. The paper contains a discussion of the possibility of achieving intertemporal consistency in various ways: Through the prior commitment of actions (that is, the deliberate foreclosing of future options); through modifications in the procedure for discounting the future; and through the adoption of a dynamic-programming approach to the problem (that is, the construction of the plan by starting with the final element and successively choosing each previous element in the light of the subsequent sequence).