How GDP Is Measured, and Why It Gets Revised

Last updated October 29, 2026

Gross domestic product (GDP) is the headline measure of the U.S. economy. The Bureau of Economic Analysis (BEA) defines it as the value of the final goods and services produced in the United States. Most GDP claims, though, are about a growth rate, and that rate gets revised.

The number you usually hear is a percentage

BEA notes that U.S. GDP totals trillions of dollars, but the figure people usually quote is the rate of change in real GDP from the previous quarter or year. The percentage GDP grew or shrank is, in BEA’s words, an important way for Americans to gauge how the economy is doing.

Real vs. nominal

“Real” or “chained” GDP has been adjusted to remove the effects of inflation, so different periods can be compared. “Current-dollar” or “nominal” GDP is based on market prices during the period. A claim about nominal growth during high inflation can look much stronger than real growth for the same quarter.

Three estimates for each quarter

BEA estimates GDP for each quarter three times, which is why new GDP statistics come out every month. The advance estimate arrives about a month after the quarter ends and is an early look based on the best information available then. The second and third estimates each add source data that weren’t available the month before, improving accuracy. BEA also has a video on why old GDP numbers change.

Who uses GDP

BEA says the White House and Congress use GDP numbers to plan spending and tax policy, the Federal Reserve uses them in setting monetary policy, and state and local governments and businesses rely on them too. BEA also estimates GDP by state, county, U.S. territory and industry.

How GDP claims go wrong

Comparing estimates of different vintages. An advance estimate and a later revised estimate for the same quarter can differ.
Nominal vs. real. Check whether inflation has been removed.
Quarter vs. year. A quarterly rate and an annual change answer different questions.
National vs. state. State GDP is a separate BEA series.

Checklist for GDP claims

Real or nominal?
Which quarter or year, and which estimate (advance, second, third, or later revision)?
Growth rate or dollar level?
National, state or industry?

GDP below the national level

BEA also produces GDP for smaller areas and sectors, and each has its own schedule:

States: quarterly and annual estimates for each state and D.C., with industry breakdowns.
Counties: released annually, covering 34 industries. BEA says its first official GDP statistics for the nation’s 3,113 counties and county equivalents came out in December 2019.
U.S. territories: annual reports for American Samoa, the Northern Mariana Islands, Guam, Puerto Rico and the U.S. Virgin Islands.
Industries: quarterly and annual “value added” by industry, plus gross output, compensation, operating surplus and taxes.

A claim about a state or county economy should cite these series, not national GDP.

Sources

BEA: Gross Domestic Product (Learning Center). Checked October 29, 2026.

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Last updated October 29, 2026. Facts checked October 29, 2026 against the official sources linked above. EvenFacts is independent and isn’t affiliated with any government agency, party or candidate. This explainer is general information, not legal or financial advice, and it doesn’t take a side.