What influences a decision? Some results from a highly controlled defence game

A closed game is described in which one person, representing a land force commander, plays against an unknown but pre-determined threat and decides when and where to deploy reserves. The game was designed to investigate the value of various levels of intelligence data. But large changes in data have had little effect on the quality of decisions made; the dominant feature is the variation between players. The possibility that the game itself might add unnecessarily to this variation has been examined. Accepting that large variation between players may be a fact of life, a way of increasing the efficiency of highly controlled games has also been tested. A number of working hypotheses, thought to be independent of the defence context, are offered to future game designers and the question is raised as to why Operational Researchers, who claim to assist decision-taking, know so little about what influences a decision.