In the profit environments, efficiency and effectiveness are the same. Among the models of interest in operations research are those dealing with break even analyses, linear programming, project management and network flow applications, waiting line and queuing theory. Some of these models are deterministic, others stochastic. Deterministic models assume certainty, even though analysts do not know precisely the value of the variables in the models. This is a simplifying assumption which allows analysts to address complex problems.
Stochastic models assume probabilistic distributions for the values of variables in models.
This makes analyses more difficult, but allows for the specification of results in confidence intervals, a more precise way of specifying the answers from the models. Break even analyses is a straight forward, deterministic approach to determine the trade-offs between fixed and variable costs relative to revenues. By properly equating the sum of fixed and variable costs to the total revenues for a product, the total sales necessary to break even can be derived. Managers can then compare this mathematically derived quantity to the marketing projection to determine whether to proceed with the product. With a limited set of resources the manager can decide the mix of products to make which will optimize the economic criteria.