AVERAGE-MARGINAL RULE: An intriguing, extremely useful mathematical relationship between an average measure and it's corresponding marginal measure, for example average product and marginal product, or average total cost and marginal cost. When the marginal measure is greater than the average measure, then the average measure increases. Alternatively, when the marginal measure is less than the average measure, then the average measure decreases. In addition, when the marginal measure is equal to the average measure the average measure doesn't change. See also | average product | marginal product | average total cost | average variable cost | marginal cost | average revenue | marginal revenue | average factor cost | marginal factor cost | average revenue product | marginal revenue product |
