A Vietnam Simulation: a Report On the Canadian/English Joint Project

This paper begins with a discussion of models in which two complementary sets of ideas are contrasted. The first set of ideas come from a political scientist, and the second set from an operational researcher. This discussion of models leads naturally to a consideration of simulations from the same two points of view. A difference between the two particular views presented here is that the political scientist views simulation as a model, while the operational researcher views simulation as experimentation on a model.In discussing the Vietnam simulation particular attention is given to the problem of selecting participants on the basis of political ideology. An important point from this discussion concerns the difficulties of trying to use such a simulation to study policy. [A fairly complete technical description of the assumptions and methodology of the simulation is also included in the Appendix.]The question of the validity of simulations in some detail. The first of these sections discusses ideas on isomorphism and homomorphism, while the second discusses ideas on validation with reference to experiences with, and outcomes from, the development runs of the Vietnam simulation. This section strengthens the earlier suggestion that the Vietnam simulation is at present best seen as a valuable heuristic and not as a policy-testing instrument.In the final policy implications sections, it is suggested that ( I ) some efforts are made to show the validity of the simulation before attempting to evaluate policies, and (2) governments concerned with the Vietnam situation use the simulation as an aid to thinking about the Vietnam situation.