maximin strategy a strategy that maximizes an agent’s minimum gain, or equivalently, minimizes his maximum loss. Writers who work in terms of loss thus call such a strategy a minimax strategy. The term ‘security strategy’, which avoids potential confusions, is now widely used. For each action, its security level is its payoff under the worst-case scenario. A security strategy is one with maximal security level. An agent’s security strategy maximizes his expected utility if and only if (1) he is certain that ‘nature’ has his worst interests at heart and (2) he is certain that nature will be certain of his strategy when choosing hers. The first condition is satisfied in the case of a two-person zero-sum game where the payoff structure is commonly known. In this situation, ‘nature’ is the other player, and her gain is equal to the first player’s loss. Obviously, these conditions do not hold for all decision problems. See also DECISION THEORY, GAME THEORY. B.Sk.