Chapter 13: Costs of Production

The goal of firms is to maximize profit, which equals total revenue minus total cost. When analyzing a firm’s behavior, it is important to include all the opportunity costs of production. Some of the opportunity costs, such as the wages a firm pays its workers, are explicit. Other opportunity costs, such as the wages the firm owner gives up by working in the firm rather than taking another job, are implicit. A firm’s costs reflect its production process. A typical firm’s production function gets flatter as the quantity of an input increases, displaying the property of diminishing marginal product. As a result, a firm’s total-cost curve gets steeper as the quantity produced rises. A firm’s total costs can be divided between fixed costs and variable costs. Fixed costs are costs that do not change when the firm alters the quantity of output produced. Variable costs are costs that do change when the firm alters the quantity of output produced. From a firm’s total cost, two related measures of cost are derived. Average total cost is total cost divided by the quantity of output. Marginal cost is the amount by which total cost would rise if output were increased by 1 unit. When analyzing firm behavior, it is often useful to graph average total cost and marginal cost. For a typical firm, marginal cost rises with the quantity of output. Average total cost first falls as output increases and then rises as output increases further. The marginal-cost curve always crosses the average-total-cost curve at the minimum of average total cost. A firm’s costs often depend on the time horizon being short run but variable in the long run. As a result, when the firm changes its level of production, average total cost may rise more in the short run than in the long run. Overall, I think this chapter was relatively easy to understand.