Business Cycle
What is Business Cycle?
The business cycle is the fluctuation in economic activity over time, characterized by periods of expansion and contraction.
The business cycle represents the ups and downs in an economy's overall output, employment, and income. It consists of four main phases: expansion, peak, contraction, and trough. During an expansion, economic activity increases, while during a contraction, it decreases. The business cycle is influenced by various factors, including changes in consumer spending, business investment, government policies, and international events.
Business Cycle: a worked example
Calder's real GDP traces one full cycle and the start of the next. Output bottoms at $460B in the first trough, climbs to a peak of $520B, slides to a second trough of $495B, then rises to a new peak of $560B. The first expansion is (520 minus 460) ÷ 460 × 100 = 13.0%. The contraction that follows is (495 minus 520) ÷ 520 × 100 = negative 4.8%. The second expansion is (560 minus 495) ÷ 495 × 100 = 13.1%. Notice that the second trough of $495B sits well above the first trough of $460B, because potential output keeps rising while the cycle swings around that upward trend. Unemployment moves inversely, running near 8% at each trough and near 4% at each peak.
The mistake students make with business cycle
Price data gets mistaken for the cycle. Students see a rising CPI or a rising nominal GDP figure and label the economy as expanding, since both numbers point up. The business cycle is measured in real terms: real GDP, employment, and real income. A nation whose nominal GDP grows 6% while prices rise 7% is contracting in real terms, so the correct reading is a contraction with inflation, not an expansion. Deflate the figures before deciding which phase the economy is in.
Business Cycle questions
What are the four phases of the business cycle?
Expansion, peak, contraction, and trough. Expansion is the stretch of rising real GDP and falling unemployment. The peak is the turning point where output stops rising. Contraction, called a recession once it is deep and long enough, brings falling output and rising unemployment. The trough is the bottom, where output stops falling and the next expansion begins. The phases always repeat in that order but vary widely in length and depth.
What causes the business cycle?
Swings in aggregate demand drive most short-run fluctuations. A drop in consumer confidence, a pullback in business investment, tighter credit, or falling exports shifts aggregate demand left and pulls real GDP below potential. Supply shocks such as a sudden jump in energy costs shift short-run aggregate supply instead, producing a contraction with rising prices. Inventory swings, the spending multiplier, and delayed policy responses amplify whatever starts the move.
Is the business cycle the same as economic growth?
Growth and the cycle work on different time horizons. Long-run growth raises potential output by adding capital, labor, technology, or better institutions, which shifts the long-run aggregate supply curve and the production possibilities curve outward. The business cycle is the short-run wobble of actual output around that rising potential path. An economy can be deep in a contraction while its long-run growth trend is still positive.
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