Chapter 11: Technology, Production, and Costs – Microeconomics Study Notes

Technology, Production, and Costs

Introduction

This chapter explores how firms transform inputs into outputs, the role of technology and technological change, and how production decisions affect costs in both the short run and long run. Understanding these concepts is essential for analyzing firm behavior and market outcomes in microeconomics.

1. Technology: An Economic Definition

Definition and Examples

• Technology: The processes a firm uses to turn inputs into outputs of goods and services.

• Inputs may include labor (L), capital (K), buildings, equipment, and knowledge.

• Technological change: A change in a firm's ability to produce a given level of output with a given quantity of inputs.

• Example: Improvements in inventory control at Wal-Mart allow the firm to produce the same output with fewer inputs, reducing costs.

2. The Short Run and the Long Run in Economics

Time Horizons in Production

• Short run (SR): A period during which at least one input is fixed (usually capital, K), while other inputs (like labor, L) are variable.

• Long run (LR): A period in which all inputs can be varied, new technology can be adopted, and the size of the physical plant can be changed.

• Assumptions:

  • Production is efficient: maximum output using minimum input.

  • At least one input cannot be changed immediately in the short run.

3. Costs: Variable and Fixed

Types of Costs

• Total cost (TC): The cost of all inputs a firm uses in production.

• Variable costs (VC): Costs that change as output changes (e.g., wages, raw materials).

• Fixed costs (FC): Costs that remain constant as output changes; also called sunk costs (e.g., rent, equipment).

• Formula:

  • $TC = FC + VC$

Explicit vs. Implicit Costs

• Explicit cost: A cost that involves spending money (accounting cost).

• Implicit cost: A nonmonetary opportunity cost (e.g., foregone salary, interest).

• Opportunity cost: The highest-valued alternative that must be given up to engage in an activity.

• Economic cost: $\text{Economic cost} = \text{Explicit cost} + \text{Implicit cost}$

Table: Jill Johnson's Costs per Year

Cost Item	Amount ($)
Pizza dough, tomato sauce, other ingredients	20,000
Wages	48,000
Interest payments on loan	10,000
Electricity	6,000
Lease payment for store	24,000
Foregone salary	30,000
Foregone interest	3,000
Economic depreciation	10,000
Total	151,000

Table: Joe, Software Engineer – Monthly Costs

Explicit Costs	Amount ($)	Implicit Costs	Amount ($)
Office furniture (rental)	1,000	Foregone salary	4,000
Utilities	200	Foregone rent	1,000
Office cleaning & coffee	600	Foregone interest	1,000
Total explicit cost	1,800	Economic depreciation	1,000
Accounting Profit: $8,200		Economic Profit: $2,100

4. The Production Function

Definition and Representation

• Production function: The relationship between the inputs employed by a firm and the maximum output it can produce with those inputs.

• Represents the firm's technology and the combinations of inputs that yield the same amount of output.

5. Short-Run Production and Cost

Average Total Cost (ATC)

• Average total cost (ATC): Total cost divided by the quantity of output produced.

• Formula: $ATC = \frac{TC}{Q}$

Table: Short-Run Production and Cost at Jill Johnson's Restaurant

# Workers (L)	# Pizza Ovens (K)	Quantity of Pizzas (Q)	Cost of Pizza Ovens (FC)	Cost of Workers (VC)	Total Cost (TC)	ATC
0	2	0	$800	$0	$800	–
1	2	200	$800	$650	$1,450	$7.25
2	2	450	$800	$1,300	$2,100	$4.67
3	2	550	$800	$1,950	$2,750	$5.00
4	2	600	$800	$2,600	$3,400	$5.67
5	2	625	$800	$3,250	$4,050	$6.48
6	2	640	$800	$3,900	$4,700	$7.34

U-Shaped ATC Curve and Law of Diminishing Returns

• The ATC curve is U-shaped in the short run due to the law of diminishing returns.

• As more of a variable input (labor) is added to a fixed input (capital), the marginal product of labor eventually declines.

6. Marginal Product of Labor

Definition and Calculation

• Marginal product of labor (MPL): The additional output a firm produces as a result of hiring one more worker.

• Formula: $MPL = \frac{\Delta Q}{\Delta L}$

• Example: If hiring a second worker increases output from 200 to 450 pizzas, $MPL = 250$.

Table: Marginal Product of Labor at Jill Johnson's Restaurant

L	K	Q	MPL
0	2	0	–
1	2	200	200
2	2	450	250
3	2	550	100
4	2	600	50
5	2	625	25
6	2	640	15

Law of Diminishing Returns

• In the short run, adding more of a variable input to a fixed input causes the marginal product of the variable input to decline.

• Initially, specialization and division of labor increase MPL, but eventually diminishing returns set in.

7. Relationship Between Short-Run Production and Short-Run Cost

Marginal Cost (MC)

• Marginal cost: The change in total cost from producing one more unit of output.

• Formula: $MC = \frac{\Delta TC}{\Delta Q}$

• Example: If total cost increases from $25 to $75 when output increases from 0 to 625,$MC = \frac{75-25}{625-0} = 0.08$

U-Shaped MC and ATC Curves

• For initial workers, MPL increases, causing MC to fall.

• For later workers, MPL falls, causing MC to rise.

• MC curve is U-shaped due to the law of diminishing returns.

• Relationship between MC and ATC:

  • When MC < ATC, ATC is decreasing.

  • When MC > ATC, ATC is increasing.

8. Graphing Family of Cost Curves

Definitions and Formulas

• Average fixed cost (AFC): $AFC = \frac{FC}{Q}$

• Average variable cost (AVC): $AVC = \frac{VC}{Q}$

• Average total cost (ATC): $ATC = \frac{TC}{Q}$

• Relationship: $ATC = AFC + AVC$

Properties of Cost Curves

• MC, ATC, and AVC are all U-shaped.

• MC curve intersects both AVC and ATC at their minimum points.

• As output increases, AFC gets smaller and the difference between ATC and AVC decreases.

9. Costs in the Long Run

Long-Run Average Cost Curve (LRAC)

• In the long run, all costs are variable; there are no fixed costs.

• LRAC: Shows the lowest cost at which a firm can produce a given quantity of output when no inputs are fixed.

Economies and Diseconomies of Scale

• Economies of scale: LRAC falls as output increases.

• Minimum efficient scale: The level of output at which all economies of scale are exhausted.

• Constant returns to scale: LRAC remains unchanged as output increases.

• Diseconomies of scale: LRAC rises as output increases.

Table: Summary of Definitions of Cost

' []pTerm	Definition	Symbol/Equation
Total cost	All inputs used by a firm	TC
Fixed cost	Costs constant as output changes	FC
Variable cost	Costs change as output changes	VC
Marginal cost	Increase in TC from producing one more unit	$MC = \frac{\Delta TC}{\Delta Q}$
Average total cost	TC divided by output	$ATC = \frac{TC}{Q}$
Average fixed cost	FC divided by output	$AFC = \frac{FC}{Q}$
Average variable cost	VC divided by output	$AVC = \frac{VC}{Q}$
Implicit cost	Nonmonetary opportunity cost	–
Explicit cost	Spending money	–

10. Common Pitfalls

• Do not confuse diminishing returns (short run, marginal cost curve slopes upward) with diseconomies of scale (long run, LRAC curve slopes upward).

Conclusion

Understanding technology, production functions, and cost curves is fundamental for analyzing firm behavior in microeconomics. These concepts explain how firms make decisions about output, pricing, and scale, and how costs change in the short run and long run.