Firms in Perfectly Competitive Markets

Comprehensive review flashcards covering Chapter 10: Firms in Perfectly Competitive Markets, including market structures, profit maximization rules, short-run shutdown criteria, cost curve geometry, long-run entry and exit, and economic efficiency.

What are the three fundamental characteristics of a perfectly competitive market according to Chapter 10?

A perfectly competitive market has: (1) many buyers and sellers, all small relative to the market, (2) all firms selling identical (homogeneous) products, and (3) no barriers to new firms entering the market.

What five simultaneous criteria define perfect competition according to Dr. Colin Mang's lecture notes?

1. Many buyers and sellers (each small relative to market size);
2. Homogeneous goods (perfect substitutes);
3. Perfect information about prices and product quality;
4. No additional transaction costs;
5. Free entry and exit of firms.

What is a price taker, and why is an individual firm in a perfectly competitive market considered one?

A price taker is a buyer or seller unable to affect the market price. An individual firm is a price taker because its output is negligible relative to total market output and it sells identical products to competitors; charging above the market price results in zero sales, while charging the market price allows it to sell all it wants.

How does the demand curve facing an individual perfectly competitive firm differ from the overall market demand curve?

The individual firm faces a horizontal (perfectly elastic) demand curve at the prevailing market price ($d = MR = P$), whereas the overall market demand curve is downward sloping.

Why is Zoom Video Communications not considered a firm in a perfectly competitive market?

Zoom sells video conferencing services that are differentiated and not identical to competitors such as Microsoft's Teams, Cisco, and Google, meaning Zoom does not face a horizontal demand curve.

Why do economists study the model of perfect competition even though few real-world markets meet all of its conditions?

It serves as an essential benchmark representing the maximum possible competition against which actual markets can be evaluated, reflecting George Stigler's principle that abstract scientific models must deal broadly with phenomena rather than being descriptive of only one.

What are the four market structures classified by economists, and what is an example of each?

1. Perfect competition (e.g., wheat farming, corn growing);
2. Monopolistic competition: many firms, differentiated products (e.g., restaurants, clothing stores);
3. Oligopoly: few firms (e.g., streaming services, automobile manufacturing);
4. Monopoly: one firm (e.g., mail delivery by Canada Post).

How do Adam Smith's concept of the 'invisible hand' and Michael Polanyi's idea of 'spontaneous order' explain market equilibrium?

Adam Smith's 'invisible hand' explains how decentralized, self-interested decisions lead unintentionally to coordinated social outcomes. Michael Polanyi's 'spontaneous order' illustrates that market equilibrium arises without centralized command, analogous to individual families shoveling their sidewalks after a snowstorm and collectively clearing the entire block.

Why does $P = MR = AR$ hold true for an individual firm in a perfectly competitive market?

Because the firm is a price taker and can sell any quantity at the fixed market price $P$. Each additional unit sold adds exactly $P$ to total revenue ($MR = P$), and total revenue divided by quantity always equals $P$ ($AR = \frac{TR}{Q} = P$).

According to the total revenue ($TR$) and total cost ($TC$) diagram, at what point does a firm maximize total profit?

Profit is maximized at output $q^*$, where the vertical distance between the $TR$ curve and $TC$ curve is greatest, which occurs where their slopes are equal, meaning $MR = MC$.

Why should a firm continue expanding output as long as $MR > MC$ rather than stopping where profit per unit is maximized?

As long as $MR > MC$, selling an additional unit adds more to total revenue than to total cost, which increases total profit. Firms seek to maximize total profit ($TR - TC$), not profit per unit sold.

If Farmer Parker sells wheat at a market price of $\\text{\$}5.50$ per bushel and has a total cost of $\\text{\$}29.00$ when producing $6$ bushels (where $MR = MC$), what is his total profit?

\text{Total Profit} = TR - TC = (\5.50 \times 6) - \$29.00 = \$33.00 - \$29.00 = \$4.00$.

If Farmer Parker's fixed cost increases from $\\text{\$}10.00$ to $\\text{\$}20.00$, what happens to his profit-maximizing output and total profit?

His profit-maximizing output remains unchanged because an increase in fixed cost does not change marginal cost ($MC$), so $MR = MC$ occurs at the same output level. However, his total profit decreases by $\\text{\$}10.00$ (e.g., from $\\text{\$}13.50$ to $\\text{\$}3.50$).

How is a firm's total profit or loss illustrated as an area on a cost curve graph?

It is illustrated as a rectangle whose height is the difference between price ($P$) and average total cost ($ATC$) at the profit-maximizing quantity, and whose width is the quantity produced ($Q$): $\text{Profit} = (P - ATC) \times Q$.

Based on the cost and revenue curves for Andy's basketball firm, how are the profit-maximizing output and total profit determined when the market price is $\\text{\$}12.50$?

Andy maximizes profit by producing $6$ basketballs per day where $MR = MC = \$12.50$. At $Q = 6$, $ATC = \$9.25$, so total profit is the shaded rectangular area: $(\$12.50 - \$9.25) \times 6 = \$75.00 - \$55.50 = \$19.50$.

Based on the cost curves for Andy's basketball firm, what is the loss-minimizing output and economic loss when the market price falls to $\\text{\$}6.00$?

Andy minimizes loss by producing $4$ basketballs per day where $MR = MC = \$6.00$. At $Q = 4$, $ATC = \$8.50$, resulting in an economic loss represented by the shaded rectangle: $(\text{Total Revenue} - \text{Total Cost}) = (4 \times \$6.00) - \$34.00 = \$24.00 - \$34.00 = -\$10.00$.

In Frances's pencil production example, what output should she produce at a price of $\\text{\$}1.80$, and what is her profit?

Frances should produce $6$ pencils per day because the 6th pencil's $MC$ is $\\text{\$}1.60$ ($< \$1.80$), while the 7th pencil's $MC$ is $\\text{\$}1.90$ ($> \$1.80$). Her total profit is $TR - TC = (6 \times \$1.80) - \$6.80 = \$10.80 - \$6.80 = \$4.00$.

If the price of pencils drops to $\\text{\$}1.00$, why does Frances continue to produce $5$ pencils instead of shutting down?

At $Q = 5$, her $TC$ is $\\text{\$}5.20$ and her revenue is $5 \times \$1.00 = \$5.00$, yielding a loss of $\\text{\$}0.20$. If she shuts down, her loss equals her fixed cost of $\\text{\$}1.00$. Because producing results in a smaller loss ($\\text{\$}0.20 < \$1.00$), she continues operating in the short run.

What is the short-run shutdown rule for a firm in a perfectly competitive market?

A firm will shut down temporarily in the short run if the market price falls below the minimum point of its average variable cost curve ($P < \min AVC$), meaning total revenue is less than variable cost ($TR < VC$).

Why are fixed costs considered irrelevant to a firm's short-run shutdown decision?

Fixed costs are sunk and unavoidable in the short run; the firm must pay them in full whether it produces output or shuts down completely.

In this short-run loss diagram, what do areas $A$, $B$, and $C$ represent, and why does the firm choose to produce rather than shut down?

Area $A$ represents total variable cost ($VC$), area $A + B$ represents total revenue ($TR$), area $A + B + C$ represents total cost ($TC$), and area $C$ represents total loss. The firm continues producing because total revenue ($A + B$) exceeds variable cost ($A$), covering all variable costs and a portion of fixed costs ($B$), making the operating loss ($C$) smaller than the shutdown loss ($B + C$, total fixed cost).

What constitutes the short-run supply curve for an individual perfectly competitive firm?

The firm's short-run supply curve is the portion of its marginal cost ($MC$) curve that lies above the minimum point of its average variable cost ($AVC$) curve; for prices below this point, quantity supplied is zero.

In Matt's boot business, why does he shut down if the price falls to $\\text{\$}50.00$ per pair when producing $3$ pairs of boots?

At $Q = 3$, Matt's $AVC$ is $\\text{\$}51.30$. Because the price of $\\text{\$}50.00$ is less than $AVC$, producing $3$ pairs results in a loss of $\\text{\$}103.90$ ($TR = \$150.00$, $TC = \$253.90$), which is greater than his fixed cost of $\\text{\$}100.00$ if he shuts down.

How did Netflix's financial situation in early 2001 exemplify rational short-run operation under economic losses?

Co-founder Marc Randolph noted that Netflix was making money from each customer each month (revenue exceeded variable costs), but had not yet gained enough customers to cover all fixed costs like office rent. Operating at a loss was rational because it reduced total losses compared to shutting down, which would have meant losing all revenue and absorbing the entire fixed cost.

How does economic break-even differ from accounting break-even in the case of Ankit Dhawan's startup, Virtuelly Inc.?

Accounting break-even considers only explicit, out-of-pocket costs. Economic break-even requires revenue to cover both explicit costs and implicit opportunity costs, which for Ankit included the forgone return on his Amazon stock and the full corporate salary he gave up by leaving Amazon, not just the $\\text{\$}4,000$ monthly salary he paid himself.

Why is a wheat farmer economically justified in ceasing production if the market price is $\\text{\$}2.90$ per bushel and average variable cost ($AVC$) is $\\text{\$}6.50$ per bushel?

Because the market price ($\\text{\$}2.90$) is below $AVC$ ($\\text{\$}6.50$). Continuing production would add $\\text{\$}3.60$ of variable loss per bushel on top of fixed costs, whereas shutting down limits total loss strictly to fixed costs.

How does the long-run entry and exit mechanism eliminate economic profits and losses in a competitive industry?

Positive economic profits attract new firms, increasing industry supply and driving down market price until profits reach zero. Economic losses cause existing firms to exit, decreasing industry supply and raising market price until remaining firms break even at zero economic profit.

Why will a firm continue to produce in the long run even when its economic profit is zero?

Zero economic profit means the firm is earning a normal profit: total revenue covers all explicit costs and implicit opportunity costs, so the owners are earning exactly as much as their capital and labor could earn in their next-best alternative.

If an entrepreneur earns an accounting profit of $\\text{\$}80,000$, previously earned a $\\text{\$}75,000$ salary as an economics professor, and forgave $\\text{\$}3,000$ in CD interest, what is her economic profit?

$\text{Economic Profit} = \$80,000 - \$75,000 - \$3,000 = \$2,000$.

What determines whether an industry's long-run supply curve is horizontal, upward sloping, or downward sloping?

It depends on its cost structure: constant-cost industries have a horizontal long-run supply curve (input costs remain constant as output expands); increasing-cost industries have an upward-sloping curve (input prices rise due to limited factor supplies); decreasing-cost industries have a downward-sloping curve (input prices fall due to economies of scale).

What industry cost structure is illustrated in this diagram for laptop computers, and what causes the long-run supply curve to slope downward?

It illustrates a decreasing-cost industry. An increase in laptop demand temporarily raises price to $P_3$, inducing expansion that increases orders for laptop displays. Economies of scale lower display costs, shifting assembly costs down to $ATC_2$ and $MC_2$, so entry shifts industry supply from $S_1$ to $S_2$ and lowers long-run equilibrium price to $P_2$.

Why do cage-free and pasture-raised eggs incur higher production costs than conventionally produced eggs?

They require lower chicken stocking density per unit of land, cause higher feed consumption because active hens expend more energy, and experience higher mortality and injury rates from pecking.

What egg market share data and projections were reported regarding cage-free and pasture-raised production in early 2023 and beyond?

In early 2023, $38\%$ of US egg-laying hens were cage-free (accounting for $20\%$ of total egg production) despite an avian flu epidemic that destroyed over 58 million chickens; USDA projected that $64\%$ of US hens will be cage-free by 2026, and by 2027 only $30\%$ will be raised conventionally with $70\%$ cage-free or pasture-raised.

How did secondary markets for limited-edition sneakers (e.g., StockX, GOAT) illustrate the entry and exit dynamics of perfect competition?

High initial profits from reselling limited-run sneakers (<50,000 pairs) attracted massive entry of resellers using automated bots, increasing market supply and competition. By mid-2022, resale prices fell and sellouts slowed, competing away excess economic profits toward a zero economic profit equilibrium.

What is the difference between productive efficiency and allocative efficiency?

Productive efficiency occurs when goods are produced at the lowest possible average cost ($P = \min ATC$), referring to how goods are produced. Allocative efficiency occurs when production matches consumer preferences such that the marginal benefit of the last unit equals its marginal cost ($P = MB = MC$), referring to what goods are produced.

Why does a perfectly competitive market achieve both productive and allocative efficiency in long-run equilibrium?

Free entry and exit forces market price down to the minimum of long-run average total cost ($P = \min ATC$), achieving productive efficiency. Profit maximization leads firms to produce where price equals marginal cost ($P = MC$), and consumers buy where price equals marginal benefit ($P = MB$), equating marginal benefit to marginal cost ($MB = MC$) and achieving allocative efficiency.

How did Hedrick Smith's reporting on consumer goods in 1970s Moscow illustrate the failure of the Soviet economy to achieve allocative efficiency?

Central planners produced goods that failed to match consumer preferences, leaving shortages of desired items like size 8 ballet shoes, sixth-grade textbooks, and properly fitting men's shoes, demonstrating that marginal cost did not align with consumer marginal benefit.

What is supply management in Canada, and why has it caused international trade disputes?

Supply management is a Canadian agricultural policy framework involving administered price setting, domestic supply controls (production quotas), and protective tariffs against foreign imports, particularly in dairy, poultry, and egg sectors, creating friction in international trade negotiations.