{
  "example_kind": "original synthetic manual planning case",
  "slug": "forecast-signed-error-bias",
  "title": "Read signed forecast error without hiding misses",
  "scenario": "Synthetic planning case: Four saved duration forecasts are 4,6,5 and 7 days; actual durations are 6,4,7 and 5. The declared signed error is actual minus forecast.",
  "layout": "evaluation",
  "dataset": {
    "heading": "Inspect the invented case records",
    "headers": [
      "Case",
      "Predicted days",
      "Actual days",
      "Signed error",
      "Absolute error"
    ],
    "rows": [
      [
        "A",
        "4",
        "6",
        "+2",
        "2"
      ],
      [
        "B",
        "6",
        "4",
        "−2",
        "2"
      ],
      [
        "C",
        "5",
        "7",
        "+2",
        "2"
      ],
      [
        "D",
        "7",
        "5",
        "−2",
        "2"
      ]
    ]
  },
  "derivation": "Signed mean=(2−2+2−2)/4=0 days. Mean absolute error=(2+2+2+2)/4=2 days. Cancellation in the signed mean does not erase individual misses.",
  "result": "Mean signed error is zero, while every forecast misses by two days. Report the lack of mean directional bias separately from error magnitude.",
  "boundary": "The guide separates directional cancellation from prediction-error magnitude.",
  "limitations": "Four synthetic cases cannot validate a model, independence or future error. These are illustrative held-out-style records, not real task analytics.",
  "sources": [
    "forecast"
  ],
  "tasks": [
    [
      "Freeze the error convention",
      "Evaluation owner",
      "Actual minus forecast is used for all four cases."
    ],
    [
      "Inspect direction and magnitude",
      "Reviewer",
      "Zero signed mean is shown beside two-day mean absolute error."
    ],
    [
      "Bound the interpretation",
      "Planning lead",
      "The note does not call the forecasts exact or validated from these four invented cases."
    ]
  ],
  "faqs": [
    [
      "What does a positive error mean here?",
      "Actual duration was longer than forecast under the stated actual-minus-forecast convention."
    ],
    [
      "Does zero bias prove a useful forecast?",
      "No. Magnitude, evaluation context and the decisions affected by misses still matter."
    ]
  ],
  "method_references": [
    {
      "id": "forecast",
      "title": "Forecasting: Principles and Practice — accuracy",
      "url": "https://otexts.com/fpp3/accuracy.html",
      "scope": "Genuine held-out forecast and point-error evaluation context. Binary scoring examples use their own explicit toy definitions; no real task model is validated."
    }
  ]
}