the ratio obtained by dividing the anticipated costs of a project by its anticipated benefits to obtain a measure of expected (or realized) cost per unit of benefit —note 1. cost-benefit ratio is usually based on discounted costs and incomes (or compounded costs and incomes) —note 2. ideally, costs and benefits include all costs and benefits, which implies a concern for society as a whole, but in practice this is rarely achieved —see benefit-cost ratio This definition last updated 07/28/2008