Economic Indicators and the Business Cycle

The circular flow model

The circular flow model connects households and firms through two markets: in the resource market, households sell resources (like labor) and firms buy them; in the product market, firms sell goods and services and households buy them. Money flows in a continuous loop — household spending becomes business revenue, which becomes the wages, rent, and profit paid back to households as income.

What GDP measures

GDP (Gross Domestic Product) is the total market value of all final goods and services produced within a country's borders in a given period (usually a year). Only final goods count — intermediate goods (raw cotton, thread) aren't counted separately, which is why a Value-Added approach (summing the value added at each production stage: cotton → thread → cloth → shirt) arrives at the same total as just pricing the finished shirt.

Three approaches to measuring GDP

In theory all three yield the same total:

• Expenditure Approach — add up all spending on final goods and services. This is the only approach used for calculations in this course.
• Income Approach — add up all income generated (wages, rent, interest, profit). It's conceptually important (it's why expenditure = income in the circular flow), but this course does not require calculating GDP this way.
• Value-Added Approach — sum the value added at each stage of production.

The four components

• C (Consumption) — household spending on durable goods, nondurable goods, and services.
• I_g (Gross Private Domestic Investment) — all final purchases of capital (machinery, tools, equipment) by businesses, all construction (including residential home-building), and changes in business inventories. Personal investing — buying stocks or contributing to a 401(k) — is not part of I_g; that's just moving existing financial assets around, not new production. Subtracting depreciation from I_g gives net investment (In), the actual increase in the economy's capital stock.
• G (Government Purchases) — spending by all levels of government (federal, state, local) on goods, services, and resources, including government salaries. Transfer payments (Social Security, unemployment benefits, welfare) are excluded — the government gets no good or service in return, so it's just money being redirected to be spent by someone else.
• X_n (Net Exports) — exports minus imports. If a country buys more from abroad than foreigners buy from it, X_n is negative.

GDP Component Explorer

GDP leaves out a lot of real economic activity:

• Non-market transactions — unpaid household labor, DIY home repairs, informal favors or bartering.
• The underground/illegal economy — unreported cash work, illegal sales.
• Resales of existing goods — selling an existing house or a used car isn't new production (only a newly built home counts).
• Purely financial transactions — buying stock, or receiving a savings bond as a gift, just transfers existing ownership; it isn't new output.
• Leisure time, environmental externalities (like pollution), and how income is distributed across the population.

Because of these gaps, GDP alone is an incomplete measure of a nation's well-being. Economists often use GDP per capita (GDP ÷ population) instead, since it accounts for population size and gives a more meaningful basis for comparing living standards across countries or over time.

Who counts as unemployed

Employed: has a job (full- or part-time). Unemployed: does not have a job but is actively looking for one. Anyone neither working nor looking (retirees, full-time students, discouraged workers who've stopped searching) is not in the labor force — counted in neither category.

A key limitation: if discouraged workers give up looking for work, they leave the labor force entirely — which can make the official unemployment rate look better even though the job market hasn't actually improved.

Three types of unemployment

• Frictional — temporarily between jobs: a recent graduate job-hunting, or someone who quit to search for a better fit.
• Structural — a mismatch between workers' skills and available jobs, often from technology or a permanent shift in the economy (a factory worker replaced by automation, or whose job moved overseas).
• Cyclical — caused by a downturn in the business cycle: workers laid off because overall demand for goods and services has fallen.

Full employment exists when cyclical unemployment = 0, leaving only frictional and structural unemployment. The unemployment rate at full employment is the natural rate of unemployment.

Inflation is a rise in the general price level — some individual prices may still fall, but the overall level rises.

An index number expresses a value relative to a chosen base year, scaled to 100 for easy math:

CPI (Consumer Price Index): tracks the cost of a fixed "market basket" of commonly purchased goods and services relative to a base year.

The inflation rate is the percent change in a price index (or CPI) from one period to the next.

The GDP Deflator is a broader price index covering all goods and services in GDP (not just a consumer basket like the CPI):

The deflator, the CPI, and "a price index" are really the same underlying idea — comparing current prices to base-year prices — just applied to different baskets of goods. Which term a problem uses depends on its wording, not a different concept.

• Demand-pull inflation: too much money chasing too few goods — aggregate spending grows faster than the economy's capacity to produce.
• Cost-push inflation: rising production costs (wages, raw materials) get passed on to consumers as higher prices.

Unanticipated inflation redistributes wealth

• Hurt: lenders/creditors (repaid in dollars worth less than expected), people on fixed incomes, anyone holding fixed-value savings.
• Helped: borrowers/debtors — they repay loans in dollars that buy less than the dollars they originally borrowed.

If inflation is anticipated instead, this redistribution shrinks, since interest rates and contracts can be adjusted in advance.

• Nominal GDP: the value of output measured in current-year prices — it can rise just because prices rose, with no actual increase in production.
• Real GDP: the value of output measured in constant (base-year) prices — it strips out inflation, so changes in real GDP reflect genuine changes in production.

Because it isolates actual output from price changes, real GDP — not nominal — is the more reliable indicator of whether living standards are genuinely improving over time.

A business cycle is the recurring (but not perfectly periodic) pattern of expansion and contraction in a nation's aggregate economic activity — tracked using real GDP alongside other coincident indicators like employment, income, and industrial production.

Four phases, in order: Peak → Contraction (Recession) → Trough → Expansion (Recovery) → back to a new Peak.

Potential GDP is the economy's sustainable output at full employment. The GDP gap (potential GDP − actual GDP) connects directly back to Okun's Law from Topic 2.3 — a bigger gap between the actual and natural unemployment rate implies a bigger GDP gap.