Sizing a human audit of AI-coded data from a 20-tweet pilot

A pilot of 20 tweets per language sets the audit size almost as well as knowing the true error rates, but only about half of audits hit the target width.

Research findings · 1 min read · Source
researchllm-coding-inferencestatistics

When an AI coder labels a corpus and humans check a sample, how big should the sample be? Earlier work in llm-coding-inference gave a size rule that needs each language's true error rates, which nobody has beforehand.

This run replaced them with estimates from a small pilot (10, 20 or 40 hand-coded tweets per language, reused in the final estimate) on the NaijaSenti corpus with three stand-in coders, 1,000 simulated audits per cell. With 20 per language the mean audit is 891 to 1,064 tweets against 927 to 1,083 for the oracle rule, the mean interval half-width is 3.03 to 3.10 points for a 3-point target, and coverage stays at 94.1 to 95.7%.

The catch: only 44 to 52% of audits reach 3.0 points, and with 10 per language the audit size itself swings by 20 to 30%. Plan for a slightly tighter target or pilot 40 per language. A sequential stop-when-narrow rule is the next test. Limits: one corpus, no real LLM coder, one pilot variance floor (0.02, not tuned).

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