{
  "example_kind": "original synthetic manual planning case",
  "slug": "zero-duration-milestone-boundary",
  "title": "Keep milestones separate from activity duration",
  "scenario": "Synthetic planning case: A draft gives the “proof accepted” milestone two days, while its actual reviewer activity already has a separate two-day duration.",
  "layout": "network",
  "dataset": {
    "heading": "Inspect the invented case records",
    "headers": [
      "Schedule element",
      "Model duration",
      "Meaning"
    ],
    "rows": [
      [
        "Proof review",
        "2 days",
        "Work performed"
      ],
      [
        "Proof accepted",
        "0 days",
        "Checkpoint after review"
      ],
      [
        "Print preparation",
        "1 day",
        "Starts after accepted checkpoint"
      ]
    ]
  },
  "derivation": "With the checkpoint correctly represented, the sequence is 2+0+1=3 model days. Giving both review and its acceptance event two days would produce an unsupported five-day sequence.",
  "result": "Keep the reviewer activity at two days and the acceptance milestone as a zero-duration checkpoint in this model. Do not charge the same review twice.",
  "boundary": "The artifact prevents duplicate duration when an activity and its completion event are both scheduled.",
  "limitations": "Zero is a milestone convention in this example, not an assertion that people make instantaneous decisions.",
  "sources": [
    "schedule"
  ],
  "tasks": [
    [
      "Identify work versus event",
      "Schedule owner",
      "The milestone records completion of the already-modelled proof review."
    ],
    [
      "Retain the actual review activity",
      "Reviewer",
      "Two days of review and its evidence remain visible."
    ],
    [
      "Link the next activity",
      "Production owner",
      "Print preparation starts only after the acceptance checkpoint."
    ]
  ],
  "faqs": [
    [
      "Does zero duration mean no acceptance work is needed?",
      "No. The two-day review activity supplies that work and evidence."
    ],
    [
      "Can every approval be a zero-duration milestone?",
      "An approval activity may take time; its completion event is the checkpoint. Model both meanings deliberately."
    ]
  ],
  "method_references": [
    {
      "id": "schedule",
      "title": "GAO Schedule Assessment Guide",
      "url": "https://www.gao.gov/products/gao-16-89g",
      "scope": "General schedule-model context. All records, local policies and arithmetic are original toy examples, not a certified or optimized schedule."
    }
  ]
}