{
  "example_kind": "original synthetic manual planning case",
  "slug": "redundant-route-dependence-check",
  "title": "Keep shared failure causes in a fallback review",
  "scenario": "Synthetic planning case: Two alternate delivery routes use the same required input. In an invented model that input is missing with probability 0.1; both routes otherwise succeed. A proposal treats the routes as independent backups.",
  "layout": "network",
  "dataset": {
    "heading": "Inspect the invented case records",
    "headers": [
      "Toy condition",
      "Probability",
      "Route A",
      "Route B"
    ],
    "rows": [
      [
        "Shared input missing",
        "0.1",
        "Fails",
        "Fails"
      ],
      [
        "Shared input available",
        "0.9",
        "Succeeds",
        "Succeeds"
      ]
    ]
  },
  "derivation": "The only joint failure event is the shared missing input, with supplied probability 0.1. The false independent calculation 0.1×0.1=0.01 describes a different model. Naming two routes does not create independent redundancy.",
  "result": "Both routes fail together with probability 0.1 under the declared common-input model. Squaring 0.1 to obtain 0.01 would assume away the shared dependency.",
  "boundary": "The worked case tests common-cause failure in an either-route plan, distinct from serial gates requiring both successes.",
  "limitations": "Other failures are excluded by the toy definition. This does not estimate operational reliability or establish a real backup route.",
  "sources": [
    "original"
  ],
  "tasks": [
    [
      "Map common prerequisites",
      "Route planner",
      "Both routes depend on the same named input."
    ],
    [
      "Inspect the joint failure conditions",
      "Reviewer",
      "The two supplied rows describe all events in the toy model."
    ],
    [
      "Choose a meaningful fallback",
      "Delivery lead",
      "Any alternative intended to bypass the input has its own verified requirements rather than a second route name."
    ]
  ],
  "faqs": [
    [
      "Would a different executor remove this failure?",
      "Not if that executor still needs the same absent input."
    ],
    [
      "Does 0.1 describe our real service?",
      "No. It is a supplied illustrative probability with deliberately simplified conditions."
    ]
  ],
  "method_references": [
    {
      "id": "original",
      "title": "Original worked-case definitions",
      "scope": "Definitions, policy choices, records and calculations are authored for this worksheet. No external standard, statistical validation or live product measurement is claimed."
    }
  ]
}