Key Concepts and Summary

Key Terms

accounting profit total revenues minus explicit costs, including depreciation average profit profit divided by the quantity of output produced; also known as profit margin average total cost total cost divided by the quantity of output average variable cost variable cost divided by the quantity of output constant returns to scale expanding all inputs proportionately does not change the average cost of production diminishing marginal productivity general rule that as a firm employs more labor, eventually the amount of additional output produced declines diseconomies of scale the long-run average cost of producing output increases as total output increases economic profit total revenues minus total costs (explicit plus implicit costs) economies of scale the long-run average cost of producing output decreases as total output increases explicit costs out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials factors of production (or inputs) resources that firms use to produce their products, for example, labor and capital firm an organization that combines inputs of labor, capital, land, and raw or finished component materials to produce outputs. fixed cost cost of the fixed inputs; expenditure that a firm must make before production starts and that does not change regardless of the production level fixed inputs factors of production that can’t be easily increased or decreased in a short period of time implicit costs opportunity cost of resources already owned by the firm and used in business, for example, expanding a factory onto land already owned long run period of time during which all of a firm’s inputs are variable long-run average cost (LRAC) curve shows the lowest possible average cost of production, allowing all the inputs to production to vary so that the firm is choosing its production technology marginal cost the additional cost of producing one more unit; mathematically, marginal product change in a firm’s output when it employees more labor; mathematically, private enterprise the ownership of businesses by private individuals production the process of combining inputs to produce outputs, ideally of a value greater than the value of the inputs production function mathematical equation that tells how much output a firm can produce with given amounts of the inputs production technologies alternative methods of combining inputs to produce output revenue income from selling a firm’s product; defined as price times quantity sold short run period of time during which at least one or more of the firm’s inputs is fixed short-run average cost (SRAC) curve the average total cost curve in the short term; shows the total of the average fixed costs and the average variable costs total cost the sum of fixed and variable costs of production total product synonym for a firm’s output variable cost cost of production that increases with the quantity produced; the cost of the variable inputs variable inputs factors of production that a firm can easily increase or decrease in a short period of time

Key Concepts and Summary

7.1 Explicit and Implicit Costs, and Accounting and Economic Profit

Privately owned firms are motivated to earn profits. Profit is the difference between revenues and costs. While accounting profit considers only explicit costs, economic profit considers both explicit and implicit costs.

7.2 Production in the Short Run

Production is the process a firm uses to transform inputs (e.g., labor, capital, raw materials, etc.) into outputs. It is not possible to vary fixed inputs (e.g., capital) in a short period of time. Thus, in the short run the only way to change output is to change the variable inputs (e.g., labor). Marginal product is the additional output a firm obtains by employing more labor in production. At some point, employing additional labor leads to diminishing marginal productivity, meaning the additional output obtained is less than for the previous increment to labor. Mathematically, marginal product is the slope of the total product curve.

7.3 Costs in the Short Run

For every input (e.g., labor), there is an associated factor payment (e.g., wages and salaries). The cost of production for a given quantity of output is the sum of the amount of each input required to produce that quantity of output times the associated factor payment. In a short-run perspective, we can divide a firm’s total costs into fixed costs, which a firm must incur before producing any output, and variable costs, which the firm incurs in the act of producing. Fixed costs are sunk costs; that is, because they are in the past and the firm cannot alter them, they should play no role in economic decisions about future production or pricing. Variable costs typically show diminishing marginal returns, so that the marginal cost of producing higher levels of output rises. We calculate marginal cost by taking the change in total cost (or the change in variable cost, which will be the same thing) and dividing it by the change in output, for each possible change in output. Marginal costs are typically rising. A firm can compare marginal cost to the additional revenue it gains from selling another unit to find out whether its marginal unit is adding to profit. We calculate average total cost by taking total cost and dividing by total output at each different level of output. Average costs are typically U-shaped on a graph. If a firm’s average cost of production is lower than the market price, a firm will be earning profits. We calculate average variable cost by taking variable cost and dividing by the total output at each level of output. Average variable costs are typically U-shaped. If a firm’s average variable cost of production is lower than the market price, then the firm would be earning profits if fixed costs are left out of the picture.

7.4 Production in the Long Run

In the long run, all inputs are variable. Since diminishing marginal productivity is caused by fixed capital, there are no diminishing returns in the long run. Firms can choose the optimal capital stock to produce their desired level of output.

7.5 Costs in the Long Run

A production technology refers to a specific combination of labor, physical capital, and technology that makes up a particular method of production. In the long run, firms can choose their production technology, and so all costs become variable costs. In making this choice, firms will try to substitute relatively inexpensive inputs for relatively expensive inputs where possible, so as to produce at the lowest possible long-run average cost. Economies of scale refers to a situation where as the level of output increases, the average cost decreases. Constant returns to scale refers to a situation where average cost does not change as output increases. Diseconomies of scale refers to a situation where as output increases, average costs also increase. The long-run average cost curve shows the lowest possible average cost of production, allowing all the inputs to production to vary so that the firm is choosing its production technology. A downward-sloping LRAC shows economies of scale; a flat LRAC shows constant returns to scale; an upward-sloping LRAC shows diseconomies of scale. If the long-run average cost curve has only one quantity produced that results in the lowest possible average cost, then all of the firms competing in an industry should be the same size. However, if the LRAC has a flat segment at the bottom, so that a firm can produce a range of different quantities at the lowest average cost, the firms competing in the industry will display a range of sizes. The market demand in conjunction with the long-run average cost curve determines how many firms will exist in a given industry. If the quantity demanded in the market of a certain product is much greater than the quantity found at the bottom of the long-run average cost curve, where the cost of production is lowest, the market will have many firms competing. If the quantity demanded in the market is less than the quantity at the bottom of the LRAC, there will likely be only one firm.

Self-Check Questions

1 . A firm had sales revenue of $1 million last year. It spent $600,000 on labor, $150,000 on capital and $200,000 on materials. What was the firm’s accounting profit? 2 . Continuing from Exercise 7.1, the firm’s factory sits on land owned by the firm that it could rent for $30,000 per year. What was the firm’s economic profit last year? 3 . The WipeOut Ski Company manufactures skis for beginners. Fixed costs are $30. Fill in Table 7.16 for total cost, average variable cost, average total cost, and marginal cost. Quantity Variable Fixed Total Average Variable Average Total Marginal Cost Cost Cost Cost Cost Cost 0 0 $30 1 $10 $30 2 $25 $30 3 $45 $30 4 $70 $30 5 $100 $30 6 $135 $30 TABLE 7.16 4 . Based on your answers to the WipeOut Ski Company in Exercise 7.3, now imagine a situation where the firm produces a quantity of 5 units that it sells for a price of $25 each. a. What will be the company’s profits or losses? b. How can you tell at a glance whether the company is making or losing money at this price by looking at average cost? c. At the given quantity and price, is the marginal unit produced adding to profits? 5 . If two painters can paint 200 square feet of wall in an hour, and three painters can paint 275 square feet, what is the marginal product of the third painter? 6 . Return to the problem explained in Table 7.13 and Table 7.14. If the cost of labor remains at $40, but the cost of a machine decreases to $50, what would be the total cost of each method of production? Which method should the firm use, and why? 7 . Suppose the cost of machines increases to $55, while the cost of labor stays at $40. How would that affect the total cost of the three methods? Which method should the firm choose now? 8 . Automobile manufacturing is an industry subject to significant economies of scale. Suppose there are four