TOPIC 1: Circular Flow & National Income Accounting (GDP)

Circular Flow of Income

• Definition: model of the economy showing circular flow of expenditures and incomes from decision-makers’ choices and how these interact to determine what, how, and for whom goods and services are produced.

• Economic agents: Households, Firms, Government, International sector, Financial institutions.

• Flows: Real (goods/services, resources) and monetary (money payments).

Models of the Economy

Closed Private Economy (Two-Sector)

• Sectors: Households (supply resources; purchase goods/services), Firms (hire resources; produce goods/services).

• Markets: Resource/factor market (inputs bought/sold); Product market (final goods/services sold to households).

• Flows: Real flows (goods/services) and monetary flows (payments).

Three-Sector (Open Economy) / Government Integration

• Government interacts via: purchases from product market and resource market; provides public goods (roads, schools, defence).

• Taxes fund public goods; transfer payments to households and subsidies to firms.

• Net taxes by sector:

  • households: $ext{Net Taxes} = ext{Taxes} - ext{Social welfare/transfer payments}$

  • businesses: $ext{Net Taxes} = ext{Taxes (corporate and sales)} - ext{subsidies and/or tax concessions}$

Open Economy Model

• Adds rest of the world; removes real flows to simplify; includes financial market and external sector.

• Injections vs leakages concept (e.g., injections from government and exports; leakages via savings, taxes, imports).

National Income Accounting: GDP, GNP, NDP, NNP

• GDP: total market value of all final goods/services produced within a country in a given year. Exports are included if produced domestically.

• GNP: GDP + net income from abroad (income earned by nationals abroad − income earned by foreigners domestically).

  • Alternative forms: $ext{GNP} = ext{GDP} + ext{Net income from abroad}$ or $ext{GNP} = ext{GDP} + ext{Net property income from abroad}$.

• Net Domestic Product (NDP): $ext{NDP} = ext{GDP} - ext{Consumption of Fixed Capital}$ (depreciation).

• Net National Product (NNP): $ext{NNP} = ext{GNP} - ext{Depreciation}$ (or
  $ext{NNP} = ext{GNP} - ext{Consumption of Fixed Capital}$).

• Avoidance of multiple counting: only final goods/services counted; value added approach; intermediate goods excluded to prevent double counting.

• Example concept: stages of production yield value added, not total cumulative sales.

The Expenditure Approach (GDP by expenditure)

• GDP equation: $ext{GDP} = C + IG + G + X_n$

  • $C$: Personal Consumption Expenditures (non-durable, durable, services).

    • Components: non-durable goods, durable goods, services.

  • $IG$: Gross Private Domestic Investment (final purchases of fixed capital, construction, and changes in inventories).

    • Sometimes expressed as $IG = IN + ext{Consumption of Fixed Capital}$.

  • $G$: Government Purchases (durables and non-durables; government spending on goods/services).

  • $X<em>n$: Net Exports: $X</em>n = X - M$.

• Relationship to investment and public policy: government spending is an injection; taxes are a leakage.

The Income Approach

• National income components:

  • $ext{Compensation of Employees}$

  • $ext{Rents}$

  • $ext{Interest}$

  • $ext{Proprietors' Income}$

  • $ext{Corporate income tax}$

  • $ext{Dividends}$

  • $ext{Undistributed corporate profits}$

• National Income (NY): sum of the above components.

• Adjustments to derive GDP from NY:

  • Indirect business taxes (added to prices)

  • Depreciation / Consumption of Fixed Capital (added)

  • Net Foreign Factor Income (added to GDP when moving from NY to GDP)

• GDP from NY:

  • $ext{GDP} = NY + ext{Indirect taxes} + ext{Depreciation} + ext{Net foreign factor income}$

Personal Income, Disposable Income, and Saving

• Personal Income: all income received (earned and unearned) by individuals; differs from National Income due to transfers and taxes.

• Personal Disposable Income: $ext{Disposable Income} = ext{Personal Income} - ext{Personal Taxes}$

• Personal Saving: typically $ext{Personal Saving} = ext{Disposable Income} - ext{Personal Consumption Expenditures}$

Expenditure vs Income vs Output: The National Accounts identity

• Total Output = Total Expenditure = Total Income

  • Expenditure approach measures GDP via spending.

  • Income approach measures GDP via incomes generated in production.

  • Output approach (production) measures GDP via total production value.

• Equations (identity):

  • $ext{Total Output} = ext{Total Expenditure}$

  • $ext{Total Expenditure} = ext{Total Income}$

Nominal vs Real GDP; Price Level Measures

• Nominal GDP: GDP measured at current prices.

• Real GDP: GDP adjusted for inflation (constant prices).

• Price index: $ext{Price Index} = rac{ ext{Price of market basket in a year}}{ ext{Price of market basket in base year}} imes 100$

• Real GDP: $ext{Real GDP} = rac{ ext{Nominal GDP}}{( ext{Price Index}/100)}$

• GDP Deflator: $ext{GDP Deflator} = rac{ ext{Nominal GDP}}{ ext{Real GDP}}$

Interpreting National Income Statistics

• GDP at market prices vs GDP at factor costs: market prices include indirect taxes and subsidies; factor costs exclude them.

• Real vs nominal comparisons require a common price basis; use price indices to adjust.

• Per capita GDP: $ext{GDP per capita} = rac{ ext{GDP}}{ ext{Population}}$ to compare across countries.

• Use of national accounts: track performance over time, inform policy, enable cross-country comparisons; beware cross-country differences (size, resources, climate).

Limitations of GDP

GDP is widely used to measure a country’s economic performance, but it has several shortcomings:

• Excludes Non-Market Activities
  Household work, volunteer services, and subsistence farming aren’t counted, even though they add value.

• Ignores Informal/Underground Economy
  In many countries (especially in the Caribbean), a large portion of economic activity is informal and unrecorded.

• Does Not Consider Income Distribution
  GDP may rise while inequality worsens (a small group benefits while the majority remains poor).

• Does Not Measure Well-being or Quality of Life
  Higher GDP doesn’t always mean better living conditions (e.g., more production could mean more stress, longer hours, or environmental damage).

• Environmental Costs Ignored
  GDP counts pollution-creating activities (e.g., mining, deforestation) as positive output without subtracting environmental damage.

• Does Not Reflect Sustainability
  GDP growth today may come at the expense of future generations (using up natural resources).

• Does Not Account for Leisure
  If people work longer hours to increase production, GDP rises, but well-being may fall due to less free time.