{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-12T21:17:39Z",
    "providers": [
      "Claude"
    ],
    "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify",
    "pass": 2,
    "wave": 3,
    "engine": "claude",
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-06T10:00:00Z",
      "ingestedAt": "2026-10-06T07:00:21+00:00",
      "fields": [
        "agent_conduct",
        "ethics",
        "owners"
      ]
    },
    "revisions": [
      {
        "at": "2026-10-06T22:44:22+00:00",
        "engine": "codex",
        "fields": [
          "agent_conduct",
          "definition",
          "distinguishing_features",
          "failure_modes_and_hazards",
          "purpose",
          "visual_identification"
        ],
        "answering_review": "b6f4133d4c3cc6000e80daee92635bef8fe5c2ea2eca8baf23c5c3f76dc1ce6f"
      }
    ],
    "gate": {
      "passed": true,
      "version": "1.0",
      "at": "2026-10-07T10:10:28+00:00",
      "evidence": [
        "completeness 1.00",
        "sense: Wikidata description",
        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "metaModel": {
    "id": "THING-Q22856",
    "registryId": "vr.tr.population-density",
    "name": "population density",
    "version": "0.2.0-wave.3",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "XCT.QLT"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q22856/",
  "model": {
    "registry_id": "vr.tr.population-density",
    "name": "population density",
    "purpose": "Let an agent explain population density and its variants for human and nonhuman populations, compute it from population and area or volume, relay figures from statistical or ecological sources with dates and boundaries, and note the limits of comparing densities across units.",
    "definition": "The number of individuals in a human or nonhuman population per unit area or unit volume, expressed with the population, spatial boundaries and units specified; human population density is usually expressed as inhabitants per square kilometre or square mile for countries, regions, cities and statistical units, with variants including physiological density per unit of arable land and urban density measures, and the figure depends strongly on the boundaries and spatial measure used.",
    "what_it_is_for": "Comparing how crowded areas are.",
    "affordances": [
      "explain the definition and variants",
      "compute density from population and area",
      "relay figures with sources and boundaries",
      "explain limits of comparison"
    ],
    "distinguishing_features": [
      "Density is the ratio of population to area or volume.",
      "Density depends on the boundaries used.",
      "Human population measures include variants for arable land and urban areas.",
      "Density is used in planning and ecology."
    ],
    "appearance": "Not visible; a number in tables and choropleth maps.",
    "visual_identification": [
      "Density is expressed as individuals per unit area or unit volume.",
      "Density depends on the boundaries used.",
      "Population size and growth are different measures."
    ],
    "physical_properties": [
      {
        "quantity": "world average",
        "typical_range": "about 60",
        "unit": "people per square km",
        "note": "land area; sources vary"
      },
      {
        "quantity": "range",
        "typical_range": "under 1 to tens of thousands",
        "unit": "people per square km",
        "note": "from sparse territories to dense cities"
      }
    ],
    "families_and_kinds": [
      "arithmetic density",
      "physiological density per arable land",
      "urban and residential density",
      "density of administrative units",
      "density in ecology and density dependence, a related concept"
    ],
    "related_models": [
      {
        "relation": "is a kind of",
        "target": "number density",
        "why": "people per area"
      },
      {
        "relation": "is computed from",
        "target": "population",
        "why": "the numerator"
      },
      {
        "relation": "is used in",
        "target": "urban planning",
        "why": "a main application"
      },
      {
        "relation": "is related to",
        "target": "population distribution",
        "why": "the wider pattern"
      }
    ],
    "identifiers": [],
    "standards_and_regulation": [
      "Census and statistical standards for population and area",
      "UN and national definitions of urban areas"
    ],
    "failure_modes_and_hazards": [
      "Comparing densities across mismatched boundaries can mislead.",
      "Using an area or volume measure that does not match the stated population and analytical purpose can mislead.",
      "Stale figures can mislead."
    ],
    "in_scope": [],
    "out_of_scope": [],
    "characteristics": [],
    "agent_conduct": {
      "may": [
        "Compute population density from a stated human or nonhuman population and area or volume, giving units and dates.",
        "Explain variants such as physiological and urban density.",
        "Compare densities only across matching boundaries and dates."
      ],
      "must_not": [
        "Compare densities computed over mismatched boundaries without warning.",
        "Use total area including water when land area is meant.",
        "Present stale population figures as current.",
        "Use density figures to stigmatise crowded neighbourhoods or the people who live there."
      ],
      "requires_human": [
        "Using density figures for planning or resource allocation decisions that affect residents requires human review."
      ]
    },
    "ethics": {
      "considerations": [
        "Density figures guide where services and money go.",
        "Crowding statistics have been used to stigmatise poor and migrant communities."
      ],
      "affected_parties": [
        "Residents",
        "Planners",
        "Readers of statistics"
      ]
    },
    "owners": {
      "steward": "Nobody owns the measure; national statistics offices publish the authoritative figures.",
      "master_systems": [
        "National census and statistics databases"
      ]
    }
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q22856: population density",
      "url": "https://www.wikidata.org/wiki/Q22856",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: Population density",
      "url": "https://en.wikipedia.org/wiki/Population_density",
      "url_status": "live",
      "what_it_supports": "general description of the item",
      "checked_by": "wikidata-api sitelink"
    }
  ],
  "structure": {
    "bundles": [
      {
        "id": "define",
        "name": "Define",
        "description": "What density is.",
        "rationale": "Definition.",
        "layers": [
          {
            "id": "definition",
            "name": "Definition",
            "description": "Definition and variants.",
            "findings": [
              {
                "id": "definition-finding",
                "name": "Definition",
                "description": "Definition.",
                "questions": [
                  {
                    "text": "How is population density defined, and what variants exist?",
                    "kind": "definition"
                  },
                  {
                    "text": "Is the question about population density or population size or distribution?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          },
          {
            "id": "compute",
            "name": "Compute",
            "description": "Computation.",
            "findings": [
              {
                "id": "compute-finding",
                "name": "Compute",
                "description": "Compute.",
                "questions": [
                  {
                    "text": "How is density computed, and which area is used?",
                    "kind": "action"
                  },
                  {
                    "text": "What is the result for the values in question?",
                    "kind": "measurement"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "data",
        "name": "Data",
        "description": "Figures and sources.",
        "rationale": "Data.",
        "layers": [
          {
            "id": "figures",
            "name": "Figures",
            "description": "Figures.",
            "findings": [
              {
                "id": "figures-finding",
                "name": "Figures",
                "description": "Figures.",
                "questions": [
                  {
                    "text": "What is the density of a given area, from which source, date and boundary?",
                    "kind": "measurement"
                  },
                  {
                    "text": "Is the figure sourced and dated?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          },
          {
            "id": "maps",
            "name": "Maps",
            "description": "Mapping density.",
            "findings": [
              {
                "id": "maps-finding",
                "name": "Maps",
                "description": "Maps.",
                "questions": [
                  {
                    "text": "How is density mapped, and what do gridded datasets add?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits population mapping?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "interpret",
        "name": "Interpret",
        "description": "Interpretation and limits.",
        "rationale": "Caution.",
        "layers": [
          {
            "id": "limits",
            "name": "Limits",
            "description": "Boundary effects.",
            "findings": [
              {
                "id": "limits-finding",
                "name": "Limits",
                "description": "Limits.",
                "questions": [
                  {
                    "text": "Why do densities depend on boundaries, and how are comparisons made fair?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which references are standard?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          },
          {
            "id": "uses",
            "name": "Uses",
            "description": "Uses.",
            "findings": [
              {
                "id": "uses-finding",
                "name": "Uses",
                "description": "Uses.",
                "questions": [
                  {
                    "text": "How is density used in planning, epidemiology and ecology?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits urban planning?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "learn",
        "name": "Learn",
        "description": "Teaching and history.",
        "rationale": "Study.",
        "layers": [
          {
            "id": "teach",
            "name": "Teach",
            "description": "Teaching.",
            "findings": [
              {
                "id": "teach-finding",
                "name": "Teach",
                "description": "Teaching.",
                "questions": [
                  {
                    "text": "How is population density taught, and which misconceptions arise?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits demography?",
                    "kind": "action"
                  }
                ]
              }
            ]
          },
          {
            "id": "history",
            "name": "History",
            "description": "Historical densities.",
            "findings": [
              {
                "id": "history-finding",
                "name": "History",
                "description": "History.",
                "questions": [
                  {
                    "text": "How have densities changed historically, with sources?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which entry fits urbanisation?",
                    "kind": "action"
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  },
  "openQuestions": [
    "Should urban density be a separate entry?",
    "How should census data be linked?",
    "The registry entry has merged aliases for ecology and a country case; should they be split off?"
  ],
  "statistics": {
    "bundles": 4,
    "layers": 8,
    "findings": 8,
    "questions": 16
  }
}