{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/prefer-a-test-that-kills-hypotheses",
  "id": "MHC-D-RESEARCH-0297",
  "version": "0.1.0",
  "title": "Prefer a test that kills hypotheses",
  "summary": "A test that can only confirm your favorite story is a weak detective.",
  "kind": "principle",
  "body": "Choose the next test for discrimination: ask which result would make one or more hypotheses much less plausible. Write the competing explanations before the test and predict what each would produce. A useful negative result can be progress because it shrinks the search space.",
  "limits": [
    "Operational tests may be confounded or only suggestive; preserve uncertainty when the result is not decisive."
  ],
  "topics": [
    "union-diagnostic-incident-work"
  ],
  "intents": [],
  "source_ids": [
    "RS-A4A16C807A94C9D8"
  ],
  "evidence": [
    {
      "claim": "Google SRE advises designing tests that can rule groups of hypotheses in or out when possible.",
      "source_id": "RS-A4A16C807A94C9D8",
      "role": "supports",
      "note": "Many operational tests are only suggestive; uncertainty should remain visible rather than being forced into a binary verdict.",
      "locator": "Test and Treat; test design considerations"
    }
  ],
  "use_when": [
    "The investigation has accumulated several plausible stories and more logs are not narrowing them."
  ],
  "avoid_when": [
    "Operational tests may be confounded or only suggestive; preserve uncertainty when the result is not decisive."
  ],
  "example": "Use the application's own database credentials to distinguish an authorization failure from a more general connectivity failure.",
  "check": "Before running the test, you can state at least one result that would change what you investigate next.",
  "sources": [
    {
      "id": "RS-A4A16C807A94C9D8",
      "title": "Effective Troubleshooting",
      "url": "https://sre.google/sre-book/effective-troubleshooting/"
    }
  ],
  "relations": [
    {
      "from": "MHC-D-RESEARCH-0297",
      "to": "MHC-D-RESEARCH-0298",
      "type": "useful_with",
      "url": "/knowledge/order-troubleshooting-tests-by-likelihood-and-risk"
    }
  ],
  "collections": [
    {
      "id": "RC-6F9B0E6D320D1467",
      "title": "Find the fault without making the incident harder to understand",
      "url": "/collections/find-the-fault-without-making-the-incident-harder-to-understand"
    }
  ]
}