Empiriceme · Evidence · Theorem

Neyman–Pearson Lemma

For a fixed false-positive rate, the likelihood-ratio test is the most powerful; decision rules trade Type I against Type II error.

Neyman and Pearson's 1933 result. Its institutional consequence is that every screening programme, every audit threshold and every legal standard of proof is a choice about which error to prefer.

In practice

  • A screening programme set to catch almost every case will refer many healthy people, and the threshold is a policy choice.
  • An audit rule that flags 5% of transactions has chosen how many frauds it will miss, whether or not anyone stated it.
Further reading
Wikipedia
Subject
Science & Epistemology
Essay
The ways evidence misleads

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