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Why is llms.txt getting so much attention if the effect is null?

The premise needs care: only the top-5,000 test is non-significant. The full-sample test is significant with a small reported effect size. The study does not measure why people adopt the file.

Different cohorts, different results.

Top 5,000 cited domains
Subset of the top 5,000 cited domains; not the full-sample test.
p = 0.85

Mann-Whitney U tests · 14 March 2026.

A subset result cannot establish an exact null effect or explain public interest.

The evidence.

Source
The llms.txt Effect

MeasureResult
Adoption rate

Domains with llms.txt in the study.

13.3%
Top-5,000 Mann-Whitney p-value

Subset of the top 5,000 cited domains; not the full-sample test.

0.85

What this study measured.

An observational snapshot.
Tested 14 March 2026.

Read the full methodology

Population and method

Built from HTTP scans of 37,894 AI-cited domains, linked to 337,362 citations and 882 citation snapshots in the Trakkr corpus.

Where the evidence stops

This is an observational study. It measures correlation with citation outcomes, not a controlled experiment.

Adoption is uneven by sector, so raw averages can hide category concentration in SaaS and developer tooling.

The top-5,000 test returns p=0.85. The full scanned sample returns p<0.001 with reported r=-0.065. Neither establishes a causal effect. The public aggregates do not include confidence intervals or document the cohort for citation means and medians well enough to recompute the tests.

What to do with this

  • Treat llms.txt as an optional housekeeping file, not a primary citation-growth lever.
  • Prioritize answer quality, source coverage, and page structure before spending disproportionate effort on llms.txt.
  • If you do publish llms.txt, measure discovery and crawl behavior directly instead of assuming it improved citation performance.

This answer matters because it turns a study finding into an operating rule teams can use when they decide what to publish, refresh, or measure next.

Questions about this answer.

“The premise needs care: only the top-5,000 test is non-significant. The full-sample test is significant with a small reported effect size. The study does not measure why people adopt the file.”

Mack Grenfell · Why is llms.txt getting so much attention if the effect is null?
The llms.txt Effect · Trakkr Research · Updated 4 September 2026

https://trakkr.ai/trakkr-research/llmstxt-effect/answers/why-is-llms-txt-getting-so-much-attention-if-the-effect-is-null
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