In the world of recession forecasting, few indicators have the track record of the Sahm Rule. Developed by economist Claudia Sahm in 2019, this simple indicator has identified every U.S. recession since 1970 with 100% accuracy.
Here is how it works, why it matters, and what it is currently signaling.
The Formula
The Sahm Rule is deceptively simple. It triggers a recession signal when the three-month moving average of the national unemployment rate rises by 0.50 percentage points or more relative to its low during the previous 12 months.
Mathematically:
Sahm Rule Signal = (3-month avg of UNRATE) - (minimum 3-month avg of UNRATE over prior 12 months) >= 0.50
When this threshold is crossed, the economy is either in or entering a recession.
Why It Works
The Sahm Rule works because the labor market is the most critical transmission mechanism of economic downturns. When unemployment rises rapidly, it creates a negative feedback loop:
- Job losses reduce consumer income
- Reduced income lowers consumption — 70% of GDP
- Lower consumption forces businesses to cut costs further
- More job losses follow, accelerating the cycle
The 0.50 percentage point threshold captures the point at which this feedback loop becomes self-reinforcing and difficult to reverse without policy intervention.
Historical Track Record
The Sahm Rule has a perfect record across every recession since 1970:
- 1973-1975: Triggered — oil crisis recession
- 1980: Triggered — double-dip recession
- 1981-1982: Triggered — Volcker recession
- 1990-1991: Triggered — savings and loan crisis
- 2001: Triggered — dot-com bust
- 2007-2009: Triggered — global financial crisis
- 2020: Triggered — COVID-19 recession
"An indicator with 100% accuracy over seven recessions spanning 50 years deserves serious attention. The Sahm Rule is not a theoretical model — it is an empirical fact about the relationship between the labor market and the broader economy."
Current Signal
As of the most recent data, the Sahm Rule is at an elevated level. The three-month moving average of the unemployment rate has increased measurably from its cycle low, bringing the indicator close to or at the trigger threshold.
This reading is consistent with other leading indicators. The yield curve remains deeply inverted, credit spreads are elevated, and manufacturing surveys point to contraction.
Related: 7 Recession Indicators Professional Traders Watch
Limitations
No indicator is perfect. The Sahm Rule has three important caveats:
- It triggers late in the cycle. By the time unemployment rises 0.50 points, the economy is already weakening. The yield curve inverts months to years earlier.
- It is not a forecasting tool. It identifies when a recession has likely begun, not when one will begin.
- Unique post-COVID dynamics may affect the indicator's behavior. The labor market experienced unprecedented shocks and recoveries that may alter historical relationships.
However, as a confirming indicator, it remains one of the most powerful signals available to investors. When combined with the yield curve, credit spreads, and manufacturing data, it forms a robust recession detection framework.
How to Track the Sahm Rule
The Sahm Rule indicator is published by the Federal Reserve Bank of St. Louis as the FRED series SAHM. It is updated monthly with the employment report.
Recession Today tracks the Sahm Rule alongside 20+ other indicators in our USA Risk Score, updated daily with the latest FRED data.