1. a model in which one or more of the inputs allow for random variation, thus generating a range of potential outcome values. Stochastic models are used to estimate the probabilities of various outcomes occurring under varying conditions. They are widely used in the social and behavioral sciences and also in the financial world. Compare deterministic model.

2. in artificial intelligence, a model based on co-relational analysis, usually Bayesian, used for simulating situations as well as fault diagnosis. Although mathematically well founded, unless simplifying assumptions are made, such models are computationally intractable for complex situations. See graph.