A rational decision maker will make a decision only if the additional benefit of that decision outweighs the additional cost of making the decision. They will compare the marginal benefit, or additional benefit, to the marginal cost, or additional cost, and only proceed if the marginal benefit exceeds the marginal cost. This ensures any decision made increases total benefit by more than it increases total cost.

1. A rational decisionmakertakesthe decisionif andonlyif the marginal benefitexceedsthe marginal
cost.