DP Economics HL 2.12 The Market's Inability to Achieve Equity

DP Economics HL 2.12 The Market's Inability to Achieve Equity - Full notes

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DP Economics HL | 2.12 The Market's Inability to Achieve Equity

DP ECONOMICS · UNIT 2: MICROECONOMICS

2.12

The Market's Inability to Achieve Equity

Full notes for HL · IB-style

Contents

1	Equity and equality
2	Why markets fail to achieve equity
3	Measuring inequality: Lorenz curves and the Gini coefficient
4	Taxation and equity
5	Government policies to promote equity
6	The equity and efficiency debate
7	Equity versus equality
8	Why markets produce unequal outcomes
9	Income and wealth distribution
10	Lorenz curves
11	The Gini coefficient
12	Progressive, proportional and regressive taxes
13	Marginal and average tax rates
14	Transfer payments
15	Other policies to promote equity
16	Trade-offs: equity and efficiency
17	Poverty: absolute and relative
18	Mixed review: worked problems
19	Additional exam-style practice
20	Inequality and economic growth
21	Inequality of opportunity
22	Case study: Nordic model
23	Common misconceptions and links
24	Exam-style question with markscheme
25	Check your understanding
26	Summary and topic map

These are full teaching notes. Read each section in order, try the Think about it question before you read on, and do every Quick check before moving to the next section.

Before you start

Rate yourself on each statement now, and again after you've worked through the notes. Shade R (not yet), A (getting there) or G (confident).

I can…	R	A	G
distinguish equity from equality, and horizontal from vertical equity
explain why market outcomes can be inequitable
interpret Lorenz curves and the Gini coefficient
distinguish progressive, regressive and proportional taxes and calculate tax paid
explain policies to promote equity: transfers, merit goods, minimum wages
evaluate the trade-off between equity and efficiency

2.12 is entirely Additional Higher Level content. It is not part of the SL course (inequality and poverty are covered for all students in 3.4).

Guiding questions

Is it fair that some people earn a hundred times more than others? Can markets, which reward what people own, ever deliver a fair distribution? Does redistributing income make an economy less efficient?

How this topic is examined

2.12 asks you to treat inequity as a market failure. Paper 1 essays often ask you to explain why markets produce inequitable outcomes and to evaluate a policy such as progressive taxation or a minimum wage. Paper 3 can include tax calculations using marginal tax bands.

Because equity is a normative concept, strong answers separate positive analysis (what a policy does) from value judgements (whether the result is fair), and weigh equity against efficiency.

Command term	What the examiner wants
Define	the precise meaning, ideally in the IB wording, in one or two sentences
Draw / Sketch	a fully labelled diagram with every axis, curve, equilibrium and change labelled
Explain	a causal chain linked to economic theory, usually supported by a diagram
Analyse	break a situation into its parts and trace the effects of each
Evaluate / Discuss	weigh up arguments, question assumptions and reach a justified conclusion using real-world examples
Calculate	apply each tax band in turn, add the amounts and calculate the average rate

How to use these notes

Each section teaches one part of the syllabus in full. You'll see these boxes throughout; each has one job:

Box	What it's for
Think about it	a question to get you thinking before a section; the answer comes in the section
Key point	the one idea you must not forget
Common mistake	an error examiners see every year, and how to avoid it
In the real world	where the economics shows up outside the classroom
Try this	something quick you can do yourself to test the idea
Worked example	full solutions with IB-style marks (M1 method, A1 answer, R1 reasoning)
Quick check	short questions to test yourself at the end of each section

1 Equity and equality

Equality means the same; equity means fair. They are not the same thing.

Think about it

Two workers earn very different salaries. One is a surgeon who trained for 12 years; the other is a cashier. Is the difference fair? What would make it unfair?

Equality means that everyone receives the same: the same income, the same wealth, the same outcome. Equity means fairness. A fair distribution need not be an equal one: most people think it is fair that someone who works longer hours earns more. Because 'fair' depends on values, equity is a normative concept, and people disagree about what it requires.

Economists distinguish two kinds of equity in taxation and policy. Horizontal equity means that people in the same circumstances are treated the same: two people with the same income pay the same tax. Vertical equity means that people in different circumstances are treated differently in a fair way: people with higher incomes pay more tax, and often a higher proportion of their income.

Term	Meaning	Example
Equality	everyone receives the same	a flat payment of $500 to every household
Equity	fairness, a value judgement	a tax system judged 'fair' by society
Horizontal equity	equal treatment of people in equal circumstances	two workers on $40 000 pay the same tax
Vertical equity	fair differences in treatment of people in different circumstances	a higher tax rate on higher incomes

Quick check

1. Why is equity a normative concept?

2. Define vertical equity.

Answers: 1. fairness depends on value judgements 2. people with higher incomes pay more tax

2 Why markets fail to achieve equity

Markets reward what people own and can sell, not what they need.

In a market economy, incomes come from selling the services of factors of production: wages for labour, rent for land, interest for capital and profit for enterprise. How much a person earns therefore depends on what factors they own and how much the market values them. Markets have no built-in mechanism for fairness.

Unequal ownership of factors. Some people own land, shares and businesses; many own nothing but their labour. Returns to capital flow mainly to the already wealthy, and wealth is often inherited, so inequality persists across generations.

Differences in human capital. Workers with scarce skills and high education earn much more than unskilled workers. But access to education and health care often depends on family income, so differences in opportunity become differences in income.

Discrimination. Workers may be paid less, or denied jobs, because of gender, ethnicity, religion or disability, regardless of their productivity.

Market power. Firms with monopoly power and powerful individuals can capture large incomes, while workers without bargaining power may be paid less than their contribution.

Merit goods. Markets ration health care and education by ability to pay. Low-income households consume less of them, which reduces their future earnings and reinforces inequality.

Inheritance and luck. Accidents of birth, health and chance shape incomes in ways most people would not call 'earned'.

Key point

Markets can allocate resources efficiently while producing a distribution of income that most people consider unfair. Efficiency and equity are different goals.

Quick check

1. Why does unequal ownership of capital cause inequality?

2. How can markets for education reinforce inequality?

Answers: 1. returns to capital go to those who already own it; wealth is inherited 2. access depends on income, so the poor gain fewer skills and earn less

3 Measuring inequality: Lorenz curves and the Gini coefficient

One diagram and one number summarize a whole country's income distribution.

The Lorenz curve plots the cumulative percentage of the population (from poorest to richest) on the horizontal axis against the cumulative percentage of income they receive on the vertical axis. If income were perfectly equal, the poorest 20% would receive 20% of income, the poorest 40% would receive 40%, and so on: the curve would be the 45° line of equality. The further the Lorenz curve bows away from the line of equality, the more unequal the distribution.

Figure 1. Lorenz curves: country Y's curve is further from the line of equality, so income is more unequal.

The Gini coefficient summarizes the Lorenz curve in one number. It is the area between the line of equality and the Lorenz curve (area A) divided by the total area under the line of equality (A + B). It ranges from 0 (perfect equality) to 1 (one person has all the income). Countries such as Slovakia and Slovenia have Gini coefficients around 0.24; South Africa's is above 0.6.

Gini coefficient = A ÷ (A + B)

Common mistake

Saying a higher Gini coefficient means a poorer country. It measures inequality, not the level of income. A rich country can have a high Gini and a poor country a low one.

Quick check

1. What does the line of equality show?

2. What does a Gini coefficient of 0 mean?

3. What is area A?

Answers: 1. perfect equality: each % of population receives the same % of income 2. perfect equality 3. the area between the line of equality and the Lorenz curve

4 Taxation and equity

Who pays what share of their income decides whether a tax is fair.

Taxes are a major tool for promoting equity. Economists classify them by how the share of income paid changes as income rises.

A progressive tax takes a larger percentage of income from people with higher incomes: the average tax rate rises as income rises. Most income taxes are progressive, using marginal tax rates: higher rates apply only to the part of income above each threshold.

A regressive tax takes a larger percentage of income from people with lower incomes. Most indirect taxes, such as VAT and excise duties, are regressive in effect: everyone pays the same tax on a litre of petrol, but that tax is a larger share of a poor household's income, because poorer households spend a larger share of their income.

A proportional (flat) tax takes the same percentage of income from everyone.

Income band	Marginal tax rate
$0 to $10 000	0%
$10 001 to $30 000	10%
$30 001 to $80 000	25%
above $80 000	40%

WORKED EXAMPLE 1 Calculating income tax

Using the tax bands above, calculate the tax paid and the average tax rate for incomes of (a) $50 000 and (b) $100 000.

Solution

(a) 0% on first $10 000 = $0; 10% on next $20 000 = $2 000; 25% on remaining $20 000 = $5 000M1

Total tax = $7 000; average rate = 7 000 ÷ 50 000 = 14%A1 A1

(b) $0 + $2 000 + 25% of $50 000 = $12 500 + 40% of $20 000 = $8 000M1

Total tax = $22 500; average rate = 22.5%A1

The average rate rises with income: the tax is progressiveR1

Common mistake

Applying the top marginal rate to the whole income ('$100 000 × 40%'). Each rate applies only to the income within its band.

Quick check

1. Define a progressive tax.

2. Why are indirect taxes usually regressive?

3. Distinguish marginal and average tax rates.

Answers: 1. the average rate rises with income 2. the same tax is a larger share of low incomes 3. marginal: rate on the next dollar; average: total tax ÷ income

5 Government policies to promote equity

Taxes, transfers, services and the labour market.

Progressive taxation reduces the after-tax incomes of high earners more than those of low earners. Wealth and inheritance taxes reduce the concentration of wealth across generations.

Transfer payments are payments from the government to individuals with no goods or services given in return: unemployment benefits, pensions, child benefits, disability benefits. They raise the incomes of those with little or no market income. Means-tested benefits go only to those below an income level; universal benefits go to everyone in a group.

Provision of merit goods free or subsidized, especially education and health care, gives equal access regardless of income, and improves the human capital of poorer households, reducing future inequality.

Labour market policies include minimum wages (2.7), equal-pay and anti-discrimination laws, and support for training.

Conditional cash transfers, such as Brazil's Bolsa Família, pay low-income families on condition that children attend school and receive health checks, combining income support with investment in human capital.

Policy	How it promotes equity	Possible drawback
Progressive income tax	takes a larger share from higher incomes	disincentives to work; avoidance
Transfer payments	raise low incomes	cost; poverty trap with means-testing
Free education and health care	equal access; builds human capital	opportunity cost; quality issues
Minimum wage	raises low pay	possible unemployment
Wealth / inheritance tax	reduces wealth concentration	capital flight; valuation problems

Quick check

1. What is a transfer payment?

2. How do conditional cash transfers combine two aims?

Answers: 1. a payment with no good or service in return 2. income support plus investment in children's human capital

6 The equity and efficiency debate

Does redistribution shrink the pie it shares out?

A long-standing argument says there is a trade-off between equity and efficiency. High taxes on top earners may reduce incentives to work, invest and take risks; generous benefits may reduce the incentive to find work. Redistribution also involves administrative costs and deadweight losses from taxation. Arthur Okun described redistribution as carrying money in a 'leaky bucket': some is lost on the way.

But there are strong arguments that equity and efficiency can go together. Extreme inequality wastes talent: children from poor families who cannot access education never develop skills that would raise output. Better health and education for low-income groups raise productivity. Research by the IMF has found that very high inequality is associated with shorter and less stable periods of growth. And social stability, which high inequality can threaten, is good for investment.

The answer depends on the policy. Well-designed redistribution, such as investment in early education, may improve both equity and efficiency; badly designed taxes and benefits may harm efficiency with little gain in equity. Because equity is normative, the final judgement also depends on how much weight society gives to fairness relative to output.

7 Equity versus equality

Fairness, not sameness.

Equality means everyone receives the same; equity means fairness, which may involve treating people differently according to need. Markets reward people according to their productive resources, which may not be equitable.

WORKED EXAMPLE 2 Distinguishing (standard)

Distinguish equity from equality.

Solution

Equality: identical sharesR1

Equity: fair shares, considering needs and circumstancesR1

8 Why markets produce unequal outcomes

Unequal endowments.

Incomes in markets depend on ownership of factors (labour skills, capital, land), which are unequally distributed due to inheritance, education, health, discrimination and luck. Wealth generates further income (interest, rent, dividends), compounding inequality.

WORKED EXAMPLE 3 Sources (exam level)

Explain two reasons why market outcomes may be inequitable.

Solution

Unequal ownership of capital and wealthR1

Differences in education, skills and discrimination in labour marketsR1

9 Income and wealth distribution

Measuring the gap.

Income is a flow (earnings, interest per year); wealth is a stock (property, savings, shares). Wealth is usually much more unequally distributed than income.

Quick check

1. Why is wealth more unequal than income?

Answers: 1. it accumulates and is inherited; returns on wealth add to it

10 Lorenz curves

Visualizing inequality.

The Lorenz curve plots cumulative % of income against cumulative % of population. The line of perfect equality is the 45° line. The further the curve bows away, the greater the inequality.

Figure 2. Lorenz curves: the outer curve shows greater inequality.

WORKED EXAMPLE 4 Reading (standard)

On a Lorenz curve, the poorest 40% receive 15% of income. Interpret.

Solution

The bottom 40% earn only 15% of total incomeR1

Significant inequalityR1

11 The Gini coefficient

A single number.

Gini = area between the line of equality and the Lorenz curve ÷ total area under the line of equality. It ranges from 0 (perfect equality) to 1 (one person has everything). Typical values: Nordic countries about 0.25–0.28; USA about 0.39; South Africa about 0.63.

WORKED EXAMPLE 5 Gini (standard)

If the area between the line of equality and the Lorenz curve is 0.15 and the total area is 0.5, calculate Gini.

Solution

0.15/0.5M1

= 0.30A1

12 Progressive, proportional and regressive taxes

Who pays more?

Progressive taxes take a higher percentage from higher incomes (income tax with rising marginal rates); proportional taxes take the same percentage; regressive taxes take a higher percentage from lower incomes (many indirect taxes).

WORKED EXAMPLE 6 Regressive (exam level)

Explain why a sales tax on food is regressive.

Solution

Low-income households spend a larger share of income on foodR1

So tax paid is a larger percentage of their incomeR1

13 Marginal and average tax rates

Calculations.

The marginal tax rate is the rate on the last unit of income; the average tax rate = total tax/total income. With progressive bands, the average rate is below the top marginal rate.

Income band	Tax rate
$0–10 000	0%
$10 001–40 000	20%
over $40 000	40%

WORKED EXAMPLE 7 Calculation (exam level)

Calculate the tax and average tax rate on an income of $60 000.

Solution

20% × 30 000 = 6000; 40% × 20 000 = 8000M1

Total $14 000; average rate 23.3%A1 A1

14 Transfer payments

Redistributing income.

Transfer payments (unemployment benefits, pensions, child benefits) redistribute income to vulnerable groups without production in return. Means-tested benefits target low incomes; universal benefits go to everyone in a category.

Quick check

1. Distinguish means-tested from universal benefits.

Answers: 1. means-tested: depends on income; universal: all in a group receive it

15 Other policies to promote equity

Beyond taxes and benefits.

Policies include: free or subsidized education and healthcare, minimum wages, affordable housing, anti-discrimination laws, and universal basic income proposals.

WORKED EXAMPLE 8 Minimum wage (exam level)

Evaluate a minimum wage as a policy to reduce inequality.

Solution

Raises incomes of low-paid workersR1

May reduce employment if set too high; does not help unemployedR1

16 Trade-offs: equity and efficiency

Incentives.

High taxes and generous benefits may reduce incentives to work, save and invest (efficiency costs). However, greater equity can raise productivity through better health and education. The balance is a political choice.

Quick check

1. How might high marginal tax rates affect incentives?

Answers: 1. may reduce incentive to work extra hours or take risks

17 Poverty: absolute and relative

Different measures.

Absolute poverty: income below what is needed for basic needs (World Bank: $2.15 per day). Relative poverty: income below a proportion (often 50–60%) of median income. Multidimensional measures include health, education and living standards.

Quick check

1. Why might relative poverty rise even if everyone becomes richer?

Answers: 1. if middle incomes grow faster than low incomes

18 Mixed review: worked problems

Bringing the ideas together.

WORKED EXAMPLE 9 Mixed problem (exam level)

Explain how progressive taxation and transfer payments reduce the Gini coefficient.

Solution

Higher-income earners pay a larger share of income in taxR1

Transfers raise low incomes; Lorenz curve moves towards equalityR1

19 Additional exam-style practice

Paper 1 and Paper 3.

WORKED EXAMPLE 10 Paper 1 part (b) (exam level)

Using real-world examples, evaluate policies to reduce income inequality. [15]

Solution

Progressive taxes, transfers, minimum wage, educationR1 R1

Effectiveness and examples (Nordic countries)R1

Costs, incentives, trade-offs; judgementR1 R1

20 Inequality and economic growth

Two-way links.

High inequality may reduce growth by limiting education for the poor and social cohesion; moderate inequality may create incentives. Research by the IMF and OECD suggests high inequality tends to reduce sustained growth.

Quick check

1. Give one way inequality might harm growth.

Answers: 1. poor households cannot invest in education, reducing human capital

21 Inequality of opportunity

Starting points matter.

Inequality of opportunity arises when circumstances beyond a person's control (family background, gender, ethnicity, region) affect outcomes. Policies such as early childhood education address it.

Quick check

1. Give an example of inequality of opportunity.

Answers: 1. children from poorer families have less access to quality education

22 Case study: Nordic model

High taxes, high equity.

Nordic countries combine high taxes, extensive public services and strong social safety nets with competitive market economies, achieving low Gini coefficients and high living standards. Critics point to high tax burdens and challenges in sustaining the model.

Quick check

1. Give one feature of the Nordic model.

Answers: 1. high progressive taxes funding universal public services

23 Common misconceptions and links

Students often think…	Actually…
equity means equality	equity means fairness; it is normative
the top marginal rate applies to the whole income	each rate applies only within its band
a high Gini means a poor country	the Gini measures inequality, not income level
redistribution always reduces efficiency	some policies, such as education, can raise both

How 2.12 connects to the rest of the course

Topic	Connection
3.4 Inequality and poverty	measurement and policies for all students
2.7 Role of government	minimum wages and price controls
3.5 Fiscal policy	taxation and transfers
4.8 Measuring development	inequality-adjusted HDI

24 Exam-style question with markscheme

Try this under exam conditions (about 18 minutes) before reading the markscheme.

Figure 3. Lorenz curves for a country in 2000 and 2020.

Text A. Income inequality has risen over two decades. The government is considering raising the top income tax rate from 40% to 50% and spending the revenue on free early-childhood education.

(a) Describe the change in inequality shown. [2]

(b) Explain two reasons why the market may have produced rising inequality. [4]

(d) Calculate the tax paid on an income of $50 000 using the bands in Section 4. [2]

Markscheme

Part	Answer	Marks
(a)	inequality increased	A1
	2020 Lorenz curve further from line of equality	A1
(b)	technological change raising returns to skills	R1
	explanation	R1
	rising returns to capital / weaker unions / globalization	R1
	explanation	R1
(c)	higher top rate makes the tax more progressive	R1
	revenue funds early education for all	R1
	raises human capital of low-income children	R1
	reduces future inequality of opportunity	R1
(d)	$2 000 + $5 000	M1
	= $7 000	A1

Examiner's comments. In (c), the best answers linked both parts of the policy to equity: progressivity now and opportunity in the future. In (d), applying 25% to the whole income was the most common error.

25 Check your understanding

Section A: multiple choice

1. Equity in economics refers to

A. fairness in distribution B. equal incomes for all C. efficiency D. economic growth

2. A progressive tax is one in which

A. everyone pays the same amount B. the poor pay a higher share C. the average tax rate rises as income rises D. the rate is constant

3. A regressive tax takes

A. a larger share from the rich B. a larger share of income from low earners C. the same amount from everyone D. nothing from the poor

4. The Gini coefficient ranges from

A. 1 to 100 B. −1 to 1 C. 0 to 10 D. 0 to 1

5. Vertical equity means

A. equal incomes pay the same tax B. higher incomes pay more tax C. everyone pays the same D. taxes are regressive

6. Transfer payments include

A. unemployment benefits B. wages C. profits D. interest received

7. If rates are 0% up to $10 000 and 20% above, tax on $30 000 is

A. $6 000 B. $2 000 C. $3 000 D. $4 000

8. Wealth inequality is usually

A. smaller than income inequality B. the same C. greater than income inequality D. zero

Section B: structured

9. Explain why the market fails to achieve equity. [4]

10. Distinguish between progressive and regressive taxes, with examples. [4]

11. Evaluate the claim that reducing inequality harms efficiency. [8]

Answers

1. A 2. C 3. B 4. D 5. B 6. A 7. D 8. C

9. Incomes depend on factor ownership; unequal human capital; discrimination; market power; merit goods rationed by income.

10. Progressive: average rate rises with income (income tax); regressive: larger share from low incomes (VAT, excise duties).

11. Disincentives and deadweight loss vs wasted talent, human capital, stability; depends on policy design; judgement.

26 Summary and topic map

Idea	Remember
Equity / equality	fairness / same outcome
Horizontal / vertical equity	same treatment for same circumstances / more tax on higher incomes
Market inequity	factor ownership, human capital, discrimination, market power
Lorenz curve	further from line of equality = more unequal
Gini	A ÷ (A + B); 0 to 1
Taxes	progressive, regressive, proportional
Policies	taxes, transfers, merit goods, minimum wage

Before the exam, make sure you…

•treat equity as normative
•calculate tax band by band
•read Lorenz curves correctly
•evaluate the equity-efficiency trade-off both ways

Equity on one page

Cover this page with a sheet of paper and try to rebuild it from memory. Whatever you can't recall is what to revise next.

Figure 4. Topic map for Equity.

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