{
  "example_kind": "original synthetic manual planning case",
  "slug": "process-change-control-comparison",
  "title": "Use a contemporaneous comparison carefully",
  "scenario": "Synthetic planning case: In a toy pilot, a changed-protocol group goes from ten to eight mean minutes. A contemporaneous unchanged-protocol group goes from twelve to eleven. Their comparability is not established.",
  "layout": "evaluation",
  "dataset": {
    "heading": "Inspect the invented case records",
    "headers": [
      "Group",
      "Before mean minutes",
      "After mean minutes",
      "After minus before"
    ],
    "rows": [
      [
        "Changed protocol",
        "10",
        "8",
        "−2"
      ],
      [
        "Unchanged protocol",
        "12",
        "11",
        "−1"
      ]
    ]
  },
  "derivation": "Difference of changes=(8−10)−(11−12)=−2−(−1)=−1 minute. A shared time period alone does not prove the groups would otherwise have moved comparably.",
  "result": "The changed group decreases two minutes and comparison group one; the difference of changes is minus one minute using after-minus-before. Keep the comparability assumptions unresolved rather than declaring a causal effect.",
  "boundary": "The artifact inspects two group changes and their inference boundary, beyond a single before/after result.",
  "limitations": "This is an arithmetic example, not an identified causal estimate. No population, trend or assignment evidence is supplied.",
  "sources": [
    "nist"
  ],
  "tasks": [
    [
      "Confirm contemporaneous windows",
      "Pilot owner",
      "Both groups’ observations use the same declared before/after periods."
    ],
    [
      "Calculate both changes",
      "Reviewer",
      "The unchanged group’s one-minute decrease is not ignored."
    ],
    [
      "Review inference assumptions",
      "Method owner",
      "Group comparability and other changes remain explicit before any causal interpretation."
    ]
  ],
  "faqs": [
    [
      "Does a comparison group automatically establish causation?",
      "No. Selection, different trends and other interventions can invalidate the intended comparison."
    ],
    [
      "Why retain the unchanged group’s movement?",
      "It shows that time-related changes also occurred outside the changed protocol; interpretation still requires a justified design."
    ]
  ],
  "method_references": [
    {
      "id": "nist",
      "title": "NIST combinatorial testing",
      "url": "https://www.nist.gov/publications/combinatorial-testing",
      "scope": "Combination-coverage context. Invented review/state examples do not prove full fault coverage, certification or product behavior."
    }
  ]
}