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  "path": "/t/one-sided-significance-threshold-of-less-than-0-1-in-phase-2-clinical-trial/28645#post_3",
  "publishedAt": "2026-02-24T10:58:54.000Z",
  "site": "https://discourse.datamethods.org",
  "textContent": "agree with simon\nI would like to add that in an indication with severe mortality like AML the cost of a Type II Error is huge.\nthe worst-case scenario isn’t advancing a mediocre drug to Phase 3 (the Phase 3 trial will eventually catch that). The worst-case scenario is a Type II error (false negative)—abandoning a potentially life-saving drug because our statistical hurdles were too strict for a small sample size.\nIf we demand a strict `alpha = 0.025` (one-sided) in a Phase 2 trial, we either:\n\n  * Tank our statistical power, making it very likely that we miss active drugs.\n  * Inflate our sample size so much that the Phase 2 trial costs as much and takes as long as a Phase 3 trial.\n\n\n\nRelaxing the threshold to `10%` can be looked as an intentional trade-off. the sponsors are usually happy to accept a 1 in 10 chance of a false positive (in phase 2) to ensure we maintain 80-90% power to detect a true signal.",
  "title": "One-sided significance threshold of less than 0.1 in Phase 2 clinical trial"
}