Lakshman Achuthan is the co-founder of the Economic Cycle Research Institute (ECRI). Achuthan has nearly 30 years of experience analyzing business cycles, and has been regularly featured in the business and financial media, and as an invited speaker at a number of conferences.
Peter Westfall is a professor of statistics at Texas Tech University. He has more than 30 years of statistics experience including teaching, research, writing, and consulting. Peter teaches and performs statistical research with a focus on advanced statistical methods, regression analysis, multivariate analysis, mathematical statistics, and data mining. He specializes in using statistics in investing, technical analysis, and trading.
Kirsten Rohrs Schmitt is an accomplished professional editor, writer, proofreader, and fact-checker. She has expertise in finance, investing, real estate, and world history. Throughout her career, she has written and edited content for numerous consumer magazines and websites, crafted resumes and social media content for business owners, and created collateral for academia and nonprofits. Kirsten is also the founder and director of Your Best Edit; find her on LinkedIn and Facebook.
Understanding the Business Cycle
In essence, business cycles are marked by the alternation of the phases of expansion and contraction in aggregate economic activity, and the comovement among economic variables in each phase of the cycle. Aggregate economic activity is represented by not only real (i.e., inflation-adjusted) GDP—a measure of aggregate output—but also the aggregate measures of industrial production, employment, income, and sales, which are the key coincident economic indicators used for the official determination of U.S. business cycle peak and trough dates.
A popular misconception is that a recession is defined simply as two consecutive quarters of decline in real GDP. Notably, the 1960–61 and 2001 recessions did not include two successive quarterly declines in real GDP.
A recession is actually a specific sort of vicious cycle, with cascading declines in output, employment, income, and sales that feed back into a further drop in output, spreading rapidly from industry to industry and region to region. This domino effect is key to the diffusion of recessionary weakness across the economy, driving the comovement among these coincident economic indicators and the persistence of the recession.
On the flip side, a business cycle recovery begins when that recessionary vicious cycle reverses and becomes a virtuous cycle, with rising output triggering job gains, rising incomes, and increasing sales that feed back into a further rise in output. The recovery can persist and result in a sustained economic expansion only if it becomes self-feeding, which is ensured by this domino effect driving the diffusion of the revival across the economy.
Stages of a business cycle
Think of business cycles like the tides: a natural, never-ending ebb and flow from high tide to low tide and back again. And the same way the waves can suddenly seem to surge even when the tide’s going out or seem low when the tide’s coming in, there can be interim, contrarian bumps — either up or down — in the midst of a particular phase.
All business cycles are bookended by a sustained period of economic growth, followed by a sustained period of economic decline. Throughout its life, a business cycle goes through four identifiable phases: expansion, peak, contraction, and trough.
Expansion: Expansion, considered the “normal” — or at least, the most desirable — state of the economy, is an up period. During an expansion, businesses and companies steadily grow their production and profits, unemployment remains low, and the stock market performs well. Consumers are buying and investing, and with this increasing ›demand for goods and services, prices begin to rise too.
Several criteria determine whether the economy is in a healthy period of expansion: the GDP growth rate is in the 2% to 3% range, inflation is at the 2% target, unemployment is between 3.5% and 4.5%, and the stock market is a bull market.
Peak: The economy starts growing out of control once these numbers start to increase out of their healthy ranges. Any number of factors can throw the economy off balance. Companies may be expanding recklessly. Investors might become overconfident, buying up assets and significantly increasing their prices, which are not supported by their underlying value, creating an asset bubble. Everything starts to cost too much.
The peak marks the climax of all this feverish activity when the expansion has reached its end and indicates that production and prices have reached their limit. This is the turning point: With no room for growth left, there’s nowhere to go but down. A contraction is forthcoming.
Contraction: A contraction spans the length of time from the peak to the trough. It’s the period when economic activity is on the way down. During a contraction, unemployment numbers typically spike, stocks enter a bear market , and GDP growth is below 2%, indicating that businesses have cut back their activities.
Trough: IF the peak is the cycle’s high point, the trough is its low point. It occurs when the recession, or contraction phase, bottoms out and starts to rebound into an expansion phase — and the business cycle starts all over again. The rebound is not always quick, nor is it a straight line, along the way toward full economic recovery. The most recent trough was in April 2020.
Who measures business cycles?
In the US, business cycles are defined and measured by the National Bureau of Economic Research (NBER), a private nonprofit. NBER’s Business Cycle Dating Committee is responsible for determining the start and end of a cycle.
NBER primarily uses quarterly GDP growth rates to identify a business cycle, but it will also look at other economic indicators, such as real income, retail revenues, employment, and manufacturing output. Analysts and economists often see what they call “co-movement” in these variables, meaning the different measurements rise and fall together.
For example, if employment is up, production is likely up, as is consumer spending. Likewise, if employment is down, the other metrics are down and will eventually have an impact on GDP.