What Is a Recession? The NBER Definition vs the Two-Quarter Rule

A recession is a significant decline in economic activity, spread across the economy and lasting more than a few months; two falling GDP quarters is shorthand.

The two halves of that sentence are the two definitions in common use. In the United States the official dates come from a committee of economists at the National Bureau of Economic Research (NBER), which looks at many monthly indicators. In headlines, and in some other countries' statistical commentary, the shorthand is two consecutive quarters of falling real GDP. This page covers both, why they sometimes disagree, the indicators watched for an early read, and where Kresmion's macro regime engine fits and where it does not. It is descriptive throughout.

The official US definition: the NBER

The NBER's Business Cycle Dating Committee defines a recession as "a significant decline in economic activity that is spread across the economy and lasts more than a few months." Three criteria sit inside that sentence: depth (how far activity falls), diffusion (how widely across industries and regions) and duration (how long). The committee treats them as "somewhat interchangeable", so an extreme reading on one can partly offset a weaker reading on another, though each needs to be met to some degree.

It dates turning points by month. The month activity tops out is the peak, the month it bottoms is the trough, and the recession is the stretch between them. To place those months it reads a set of monthly series: real personal income less transfers, nonfarm payroll employment, employment from the household survey, real personal consumption expenditures, real manufacturing and trade sales, and industrial production. The NBER says that in recent decades it has put the most weight on real personal income less transfers and on payroll employment. For quarterly checks it gives equal weight to real GDP and to real gross domestic income, the same output measured from the income side.

The NBER's chronology lists these recent recessions, peak to trough:

Across 1945 to 2020, the NBER puts the average contraction at 10.3 months.

The rule of thumb: two negative quarters

The idea that a recession means two consecutive quarters of falling real GDP is a shortcut, not an official rule in the US. The UK's Office for National Statistics traces it to Julius Shiskin, then head of the US Bureau of Labor Statistics, writing a simplified definition for New York Times readers in 1974, and notes that there is no official definition of a recession. Shiskin listed it alongside other tests, such as a 1.5 percent fall in real output and a two-point rise in unemployment to at least 6 percent, but the two-quarter test is the one that stuck. As the ONS notes, commentators call an episode that meets it a "technical" recession.

The NBER's own FAQ explains why it does not use the shortcut: it does not identify economic activity with real GDP alone, real GDP could fall by small amounts in two quarters without amounting to a recession, and it prefers monthly data.

When the two definitions disagree

The two tests can point in opposite directions, and recent history has examples both ways.

Two negative quarters, no recession. On 28 July 2022 the Bureau of Economic Analysis's advance estimate showed US real GDP falling at an annual rate of 0.9 percent in the second quarter of 2022, after a 1.6 percent fall in the first quarter. In those first estimates, that met the two-quarter shortcut. The NBER did not declare a recession for 2022. Payroll employment, one of the two monthly series it weights most, rose in every month of 2022 in the current Bureau of Labor Statistics data.

A recession that ends inside two quarters. The 2020 recession ran from a February peak to an April trough, two months by the NBER's count, the shortest in its chronology. It was so deep and so widespread that it qualified on depth and diffusion despite its brevity. The Federal Reserve announced its pandemic bond purchases on 15 March 2020, between that peak and trough; quantitative easing covers how such purchases work.

GDP figures are also revised, sometimes by enough to change which quarters were negative. In the Bureau of Economic Analysis's current data, the first quarter of 2022 shows a fall of 1.0 percent and the second quarter growth of 0.6 percent, so on today's numbers 2022 no longer meets the shortcut at all. Revisions like this are one reason the NBER waits.

Why the official dates arrive late

The NBER does not call recessions in real time. Its FAQ says there is no fixed timing rule, because the committee waits long enough to avoid any doubt about a peak or trough. Its announcements page shows the December 2007 peak was announced on 1 December 2008, a year after the recession began. The FAQ gives a historical range of 4 months (the February 2020 peak, announced in June 2020) to 21 months (the March 1991 trough, announced in December 1992).

Indicators watched for an earlier read

Because the official verdict is slow, analysts watch faster indicators. None of them is an official definition, and each has given false readings.

• The Sahm rule. Created by economist Claudia Sahm, it flags when the three-month moving average of the unemployment rate rises by 0.50 percentage points or more above its lowest three-month average of the previous 12 months, as defined in the FRED series notes. It is designed to signal that a recession has begun, soon after the start, rather than to predict one.
• The yield curve. An inverted curve, with short-term Treasury yields above long-term ones, has historically preceded most US recessions, with long and variable lead times. The yield curve explainer covers the caveats, and Kresmion's yield curve tool shows the current curve and the 2-year versus 10-year spread.
• Credit spreads. The extra yield investors demand to lend to companies tends to widen when they see more default risk ahead. Federal Reserve researchers use a component of corporate spreads, the excess bond premium, in a model of the probability of a recession within 12 months. The credit spread explainer covers how those spreads are measured.
• Jobless claims, purchasing managers' surveys and data surprises. Weekly initial claims for unemployment insurance and business surveys of new orders arrive earlier than the monthly series the NBER weights most, and surprise indexes show whether incoming data are beating or missing forecasts.

Where Kresmion's macro regime fits

Kresmion's macro regime page publishes one daily reading of the cross-asset backdrop: a label from Strong Risk-Off to Strong Risk-On, the smoothed composite score behind it, its conviction, and 90 days of history, free to view. Several of the inputs above feed its growth factor, including the recent change in the 10-year minus 2-year Treasury spread (a steepening counts as growth-positive, whatever caused it), purchasing managers' surveys, weekly jobless claims and an economic surprise index that compares data releases with consensus forecasts. Credit spreads enter its liquidity and risk appetite factors. The factor breakdown opens with a free account. The regime score explainer describes how the inputs are standardized and combined.

The regime engine does not date recessions and does not estimate the probability of one. A Risk-Off label describes how markets and recent data look against their own recent history; it is not an NBER call, and the two can differ for long stretches.

Honest limitations

The NBER's dates are authoritative but arrive months late. The two-quarter shortcut is quick but can fire on small, revised declines and miss short, deep downturns. Early-warning indicators such as the yield curve (a leading indicator) and the Sahm rule (which aims to flag a recession soon after it starts) rest on a few decades of US history, a small sample of recessions, and have each produced false readings. Kresmion's regime history starts on 30 April 2026, so it has not yet lived through an NBER-dated recession, and it standardizes the recent change in each input against that input's own trailing history, which describes what is unusual now rather than what is coming.

Key takeaways

Frequently asked questions

Is a recession two quarters of negative GDP?

Not in the US. Two consecutive quarters of falling real GDP is a popular shorthand, sometimes called a technical recession, but the NBER, which sets the US dates, looks at a range of monthly indicators and judges depth, diffusion and duration. The two can disagree, as they did on the first GDP estimates for 2022.

Who declares a recession in the United States?

The NBER's Business Cycle Dating Committee, a group of academic economists. It dates the peak and trough months after the fact, and its announcements page records when each one was made.

How long does a recession last?

The NBER puts the average post-war contraction, 1945 to 2020, at 10.3 months. The range is wide: the 2020 recession lasted two months and the 2007 to 2009 recession lasted 18.

Can you know a recession has started while it is happening?

Rarely with certainty. The NBER waits until the data leave no doubt, and the December 2007 peak was announced in December 2008. Indicators such as the Sahm rule and the yield curve aim to flag a turn sooner, but they are not official and have given false readings.

Does Kresmion's regime score predict recessions?

No. It summarizes how cross-asset and macro inputs look against their own recent history as a risk-on to risk-off label. Some of its inputs are watched as recession indicators, but the score is not a recession model and does not estimate the probability of one.

This page is information, not investment advice.

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Source: NBER, Business Cycle Dating, https://www.nber.org/research/business-cycle-dating ; NBER, Business Cycle Dating Procedure: Frequently Asked Questions, https://www.nber.org/research/business-cycle-dating/business-cycle-dating-procedure-frequently-asked-questions ; NBER, US Business Cycle Expansions and Contractions, https://www.nber.org/research/data/us-business-cycle-expansions-and-contractions ; NBER, Business Cycle Dating Committee Announcements, https://www.nber.org/research/business-cycle-dating/business-cycle-dating-committee-announcements ; Office for National Statistics, "Uncertainty and the 'r' word: What exactly is a 'recession'?", https://blog.ons.gov.uk/2022/11/11/uncertainty-and-the-r-word-what-exactly-is-a-recession/ ; Timothy Taylor, "Is a Recession Defined as 'Two Negative Quarters'?" (quotes Shiskin's 1974 criteria), https://conversableeconomist.com/2022/07/25/is-a-recession-defined-as-two-negative-quarters/ ; Bureau of Economic Analysis, Gross Domestic Product, Second Quarter 2022 (Advance Estimate), https://www.bea.gov/news/2022/gross-domestic-product-second-quarter-2022-advance-estimate ; Bureau of Economic Analysis, real GDP percent change at an annual rate, current vintage as of 1 October 2026 (A191RL1Q225SBEA, via FRED), https://fred.stlouisfed.org/series/A191RL1Q225SBEA ; Bureau of Labor Statistics, All Employees, Total Nonfarm (PAYEMS, via FRED), https://fred.stlouisfed.org/series/PAYEMS ; FRED, Real-time Sahm Rule Recession Indicator (SAHMREALTIME), https://fred.stlouisfed.org/series/SAHMREALTIME ; Federal Reserve, FEDS Notes, "Updating the Recession Risk and the Excess Bond Premium" (2016), https://www.federalreserve.gov/econres/notes/feds-notes/updating-the-recession-risk-and-the-excess-bond-premium-20161006.html ; Kresmion macro regime engine (macro regime page and methodology, history from 30 April 2026).

Kresmion Research.