Simon Willison Flags Census Shift That Could Break AI Trend

Developer Simon Willison said a U.S. Census Bureau wording change Could break a 200,000-business AI adoption trend, with large firms rising from about 12% in September 2025 to about 40% by Oct. 22.

Key Takeaways

• Developer Simon Willison flagged that the U.S. Census Bureau changed a core BTOS question, potentially breaking a 200,000-company AI adoption time series
• The BTOS goes to 200,000 businesses from a pool of 1.2 million and rotates each business through the panel about every 12 weeks
• Large firms answered yes about 12% in September 2025 and about 40% by Oct. 22 under the newer wording
• The wording change shifted the question from AI in producing goods or services to AI use in any business function

AI Adoption Survey Lost Its Old Baseline

Willison’s write-up centers on the Census Bureau’s Business Trends and Outlook Survey, or BTOS, which goes to 200,000 businesses from a pool of 1.2 million and rotates each business through the panel about every 12 weeks.

Under the older wording, large companies answered yes about 12% of the time in September 2025 when asked if they used AI in producing goods or services. Under the newer wording, those same large firms were near 30% by February 2026 and about 40% by Oct. 22, when the latest data landed.

The issue is not that the Bureau stopped measuring AI, but that the old and new answers may mean different things.

A question about AI in producing goods or services will not capture the same behavior as a question about AI use in any business function, so a finance team using AI for internal paperwork counts under one wording but not the other.

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The Policy Change Matters Beyond One Chart

The Bureau’s series had become a rare public benchmark for U.S. AI uptake because banks, strategists and policy teams used it while private surveys often change sampling, wording or methodology without notice.

That makes a wording break important, because once a series changes definitions, a trend line can show acceleration even when the underlying behavior changed less than the chart suggests.

Willison tied the change to Executive Order 14434 in his analysis. The Census Bureau material he reviewed is the basis for that claim, but the agency’s own explanation and any formal methodology note will matter if the series is to remain a trusted benchmark.

From Product Use To Any Business Function

The BTOS wording change matters because it shifts the instrument’s focus from operational, customer-facing uses to the full set of business functions the survey now asks about.

A narrower question focused on producing goods or services can miss internal adoption. A broader AI adoption survey can capture HR, finance, compliance and back-office activity.

The tradeoff is continuity.

If the government widens the definition without restating the history, a public chart can stop answering the question people thought it answered, turning a clean time series into an apples-to-oranges comparison.

Investors and economists will now watch whether the Census Bureau publishes a bridge note, restates older data or keeps the new wording in place, because without that any AI adoption survey claim about a one-year surge in U.S. AI adoption needs a footnote.

How One Wording Change Alters The Trend

The BTOS is valuable because it measures the same thing over time across a very large sample, which is why an AI adoption survey is useful to Apollo Global Management, academic researchers or software buyers, since they want a trend they can compare month to month.

A wording change alters the instrument itself by expanding from direct operational use (producing goods or services) to any business function (HR, finance, compliance and back-office activity), which can raise the measured rate even if companies did not suddenly deploy far more AI in customer-facing products.

What to watch next is whether the Census Bureau publishes parallel runs, old and new wording together, for a transition period.

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