Sahm Rule History: Every US Recession Signal Since 1970, and the First False Signal (2024)

Eco3min Research · Recession Indicators

For half a century the Sahm Rule never cried wolf. In 2024 it did, then quietly took it back.

June 2026 Coverage: 1959–2026 796 monthly observations CC BY 4.0

The Sahm Rule is one of the most cited real-time recession indicators in macroeconomics. It triggers when the three-month average U.S. unemployment rate rises 0.50 percentage points above its lowest point of the prior year. Since 1970 it has crossed that threshold around the start of every U.S. recession — and produced no false signal in between.

Then, in July 2024, it triggered with no recession behind it. The reading reached 0.57 in August 2024, and the rule’s own creator immediately cautioned that it might be misreading the labor market. By April 2026 the indicator had fallen back to 0.13, and no recession had arrived. This page compiles every threshold crossing in the Federal Reserve’s real-time SAHMREALTIME series since 1959, the timing of each crossing relative to NBER recessions, and what the 2024 episode does and does not mean.

01It detects recessions in real time — it does not forecast them

The dominant description of the Sahm Rule treats it as a recession predictor. The timing record does not support that framing. Across the recessions since 1960, the threshold crossing occurred between two months before and four months after the NBER business-cycle peak, with a mean of roughly three months after the peak. By construction the rule confirms that a recession has likely already begun. Its own creator puts it plainly: “the Sahm rule is a recession indicator, not a recession forecast.”

That distinction is not a weakness — real-time identification of a downturn was its design goal — but it changes how the signal should be read. A crossing says a contraction is probably underway, not that one is coming.

02Every recession since 1970, and the one signal that reversed

The common claim is that the Sahm Rule “has never been wrong.” The real-time record is more precise, and more interesting. Since 1970 the indicator crossed its threshold around the onset of every U.S. recession with no false signal in between. The July 2024 crossing is the first of the modern era to reverse with no recession at all.

Explore the full series below. Every recession sends the indicator across the 0.50 trigger and off the top of the chart; the axis is capped so the threshold and the 2024 episode stay legible.

Vertical axis capped at 1.2. Recession spikes continue off-scale (peaks 1.53 to 9.50). Shaded bands are NBER recessions. The dashed line is the 0.50 trigger.

The table lists every crossing of the 0.50 threshold in the SAHMREALTIME series. “Months vs. NBER peak” runs from the business-cycle peak to the month of the crossing; negative means the crossing came first.

* The creator classifies the October 1969 trigger — and a December 1959 trigger at the very start of the series — as her only two false positives before 2024, since each fired shortly before the official recession start; a recession followed each within months. The indicator also re-crossed the threshold within the 1969–70 and 1973–75 recessions; those re-triggers are not counted as separate signals. A single month touched exactly 0.50 in November 1976 and reverted the next month — a one-month boundary touch, not a sustained trigger. Source: FRED SAHMREALTIME, NBER.

• Every recession since 1960 sent the indicator above 0.50, with peaks ranging from 1.53 (1990–91) to 9.50 (2020).
• The 2024 reading peaked at 0.57 — barely above the trigger — and is the only crossing since 1970 not followed by a recession.
• The crossing has lagged the recession’s official start by a mean of about three months, ranging from two months early to four months late.

03The 2024 signal triggered, then fully reversed

The indicator crossed 0.50 in July 2024 and reached 0.57 in August 2024. It then declined steadily, standing at 0.13 in April 2026 — a level associated with mid-expansion — with no NBER-dated recession in between, and it has not crossed the threshold again. The 2024 case is therefore not an open question of timing but a completed episode: the signal arose and unwound without a downturn. That makes it the first clean false signal in the real-time record since 1970.

04Why the 2024 signal did not lead to a recession

The decisive feature of 2024 is the source of the unemployment increase. The rate can rise for two very different reasons: workers losing jobs (a demand-side, layoff-led rise) or more people entering the labor force faster than they are absorbed (a supply-side rise). The Sahm Rule reacts to the rate itself and does not distinguish between them.

Through 2023 and into 2024, layoff measures such as initial jobless claims stayed low while labor force participation and immigration added job-seekers. An unemployment rate that rises because supply is expanding does not carry the self-reinforcing dynamic of one that rises because demand is contracting. The rule’s creator made exactly this point in real time: writing in her Stay-At-Home Macro newsletter in late July 2024, Claudia Sahm judged that the rule was “likely overstating the labor market’s weakening” because of unusual shifts in labor supply tied to the pandemic and immigration.

05The Sahm Rule and the yield curve: two signals, the same cycle

The 2022–2024 cycle is unusual in that two of the most-watched recession signals appeared to misfire together. The 2s10s yield curve inverted for 26 months — the longest inversion in the FRED series — and un-inverted in August 2024 with no recession. The Sahm Rule triggered in July 2024 and reversed with no recession. The two measure different things: the yield curve is a forward-looking market signal that typically leads recessions by many months, while the Sahm Rule is a coincident labor-market detector that confirms them shortly after they begin. That both pointed the same way and both proved wrong in the same cycle is what sets 2022–2024 apart. The full inversion record is in our complete history of yield curve inversions since 1976.

06Methodology & data

The indicator is the real-time Sahm Rule (FRED series SAHMREALTIME): the three-month moving average of the unemployment rate minus its minimum over the prior twelve months, computed on the data available at each historical date. The trigger threshold is +0.50 percentage points. A crossing is the first month the value reaches or exceeds 0.50 coming from below; a single month touching exactly 0.50 and reverting the next month (November 1976) is treated as a one-month boundary touch, not a sustained trigger. Recession dates are NBER business-cycle peaks and troughs. All figures here are computed by Eco3min from the public series.

import pandas as pd

# Real-time Sahm Rule straight from FRED — no API key
url = "https://fred.stlouisfed.org/graph/fredgraph.csv?id=SAHMREALTIME"
df = pd.read_csv(url, parse_dates=["observation_date"])
df.columns = ["date", "sahm"]

# Threshold crossings (from below)
trig = df["sahm"] >= 0.50
crossings = df[trig & ~trig.shift(fill_value=False)]
print(crossings[["date", "sahm"]])

07Data & reproducibility

The monthly real-time Sahm Rule series used in the chart and table is available in open format, updated when the underlying data are revised.

License: Creative Commons Attribution 4.0 (CC BY 4.0). Free for research, academic and journalistic use with attribution.

08Questions & answers

09Sources & limitations

• PrimaryFederal Reserve (FRED) — Real-time Sahm Rule Recession Indicator (SAHMREALTIME), 1959–present.
• PrimaryNBER — U.S. business cycle expansions and contractions.
• AuthorClaudia Sahm — “Sahm-thing more on the Sahm rule,” Stay-At-Home Macro (Substack), July 2024.
• OriginHamilton Project, Brookings — Recession Ready (2019), where the rule was introduced.

• The Sahm Rule is a coincident detector, not a forecast. It identifies that a recession has likely begun, on average a few months after the cycle peak; it does not anticipate one.
• It cannot distinguish demand-driven from supply-driven rises in unemployment. This is the structural limitation the 2024 episode exposed.
• Real-time vs. revised data differ around turning points. This page uses the real-time series; the revised series can read differently after the fact.
• NBER dating is retrospective. The 2024 episode is treated as complete given the full reversal to 0.13, but recession dates are assigned with a lag.