How are phases of the business cycle identified?
The business cycle describes fluctuations in economic activity through expansion, slowdown, contraction and recovery.
Mechanism and examples
Output, income, employment and sales are considered together. A peak marks movement from expansion to contraction, and a trough from contraction to recovery. One quarter or one indicator cannot reliably establish the full cycle. Analysis should state the assumption that other conditions remain unchanged, because simultaneous changes in real data can alter the outcome. In practice, it first identifies the decision makers, the price or quantity that changes, and the time horizon over which the response is measured. This explains why the same concept can produce different outcomes for households, firms and whole economies.
What matters when interpreting it?
Cycles vary in duration and severity. Seasonal movements are adjusted and data may later be revised. Long-run changes in potential growth should be distinguished from cyclical fluctuations. Data sources, periods, price adjustments and comparison groups can affect the result. To understand why an indicator changed, it is checked against related production, income, employment or price evidence. The concept should therefore be used as an analytical comparison tool with visible assumptions, not as a certain forecast or personal financial recommendation on its own.