Book cover for Intermediate Microeconomics: A Modern Approach

Intermediate Microeconomics: A Modern Approach

Hal R. Varian

ISBN #9780393927023

7th Edition

224 Questions

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Homework Questions

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Summary
Learning Objectives
Key Concepts
Example Problems
Explanations
Common Mistakes

Summary

This chapter provides a comprehensive overview of consumer's surplus, discussing both discrete and continuous methods for calculation. It differentiates consumer's surplus from producer's surplus and introduces the construction of utility from demand curves. Additional welfare measures, including compensating and equivalent variations, are explored, especially under quasilinear preferences, highlighting their role in market efficiency analyses and economic decision-making processes.

Learning Objectives

1

Explain the concept of consumer's surplus and its importance in economic analysis.

2

Differentiate between discrete and continuous methods for calculating consumer's surplus.

3

Analyze the construction of utility from demand curves and compare consumer's surplus with producer's surplus.

4

Interpret additional welfare measures like compensating and equivalent variations, especially in the context of quasilinear preferences.

Key Concepts

CONCEPT

DEFINITION

Consumer's Surplus

The difference between what consumers are willing to pay for a good and what they actually pay, representing the net benefit to consumers.

Discrete Calculation

A method of calculating consumer's surplus using distinct price and quantity levels, typically seen in simple market models.

Continuous Calculation

A method of calculating consumer's surplus using integration over a continuous demand curve, allowing for more precise measurement.

Utility Construction from Demand Curves

The process of deriving consumer satisfaction levels (utility) based on observed demand behavior and price changes.

Producer's Surplus

The difference between the amount producers actually receive from selling a good and the minimum they would be willing to accept.

Compensating Variation

A measure of the monetary amount required to restore a consumer to their original utility level after a change in prices or income.

Equivalent Variation

A measure of the monetary amount that would be equivalent to a price change from the consumer's perspective, ensuring consistent utility levels.

Quasilinear Preferences

Preferences in which one good is linear in utility, simplifying the analysis of welfare measures and gain-loss calculations.

Example Problems

Example 1

A good can be produced in a competitive industry at a cost of $\$ 10$ per unit. There are 100 consumers are each willing to pay $\$ 12$ each to consume a single unit of the good (additional units have no value to them.) What is the equilibrium price and quantity sold? The government imposes a tax of $\$ 1$ on the good. What is the deadweight loss of this tax?

Example 2

Suppose that the demand curve is given by $D(p)=10-p$. What is the gross benefit from consuming 6 units of the good?

Example 3

In the above example, if the price changes from 4 to $6,$ what is the change in consumer's surplus?

Example 4

Suppose that a consumer is consuming 10 units of a discrete good and the price increases from $\$ 5$ per unit to $\$ 6 .$ However, after the price change the consumer continues to consume 10 units of the discrete good. What is the loss in the consumer's surplus from this price change?
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Step-by-Step Explanations

QUESTION

How can you calculate consumer's surplus using the discrete method?

STEP-BY-STEP ANSWER:

Step 1: Identify the highest price a consumer is willing to pay for each unit of the good.
Step 2: Determine the actual market price paid for the good.
Step 3: For each unit purchased, calculate the difference between the willingness-to-pay price and the market price.
Step 4: Sum all these differences to obtain the total consumer's surplus.
Final Answer: The sum of these individual differences represents the consumer's surplus when using the discrete approach.

Calculating Consumer's Surplus (Discrete Method)

QUESTION

How can you calculate consumer's surplus using the continuous method?

STEP-BY-STEP ANSWER:

Step 1: Express the demand curve as a continuous function showing the relationship between price and quantity.
Step 2: Identify the maximum price (reservation price) corresponding to the quantity demanded at the observed market price.
Step 3: Set up the integral of the demand function from the market quantity to the quantity corresponding to the reservation price.
Step 4: Subtract the area under the price line (market expenditure) from the total area under the demand curve.
Final Answer: The result of the integral represents the consumer's surplus in a continuous setting.

Calculating Consumer's Surplus (Continuous Method)

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Common Mistakes

  • Believing that consumer's surplus can be directly compared to producer's surplus without understanding their distinct definitions.
  • Failing to recognize when to use discrete versus continuous methods, leading to inaccurate calculations.
  • Overlooking the importance of utility construction from demand curves in interpreting consumer behavior.
  • Confusing compensating variation with equivalent variation, especially in contexts involving quasilinear preferences.