{
  "description": "Anonymous-INCLUSIVE sensitivity variant of cohort_half_life_summary.json: first month after creation in which the share of still-active dynamic QR codes (ever-scanned base) falls below 50% of the month-1 share, with the anonymous/guest bucket included (platform-wide scope). url_only_half_life repeats the calculation for Website URL codes only. Jan-2022 is distorted in both scopes by a 98k bulk-PDF batch \u2014 the URL-only column is the robust read for that cohort.",
  "metadata": {
    "data_window_end": "2025-12-31",
    "exclusions": "Visualead-linked accounts and internal accounts excluded; the anonymous/guest creation bucket is INCLUDED (platform-wide scope, published as the disclosure contrast to the registered-account variant)",
    "sampling_rate": 1.0,
    "suppression": "all cohort bases >= 60,000 ever-scanned codes; no cells suppressed"
  },
  "rows": [
    {
      "cohort_year": 2019,
      "ever_scanned_base": 129004,
      "half_life_months": 4,
      "horizon_months": 82,
      "url_only_half_life": 4
    },
    {
      "cohort_year": 2020,
      "ever_scanned_base": 87734,
      "half_life_months": 2,
      "horizon_months": 70,
      "url_only_half_life": 2
    },
    {
      "cohort_year": 2021,
      "ever_scanned_base": 63284,
      "half_life_months": 5,
      "horizon_months": 58,
      "url_only_half_life": 5
    },
    {
      "cohort_year": 2022,
      "ever_scanned_base": 80783,
      "half_life_months": 10,
      "horizon_months": 46,
      "url_only_half_life": 5
    },
    {
      "cohort_year": 2023,
      "ever_scanned_base": 74824,
      "half_life_months": 5,
      "horizon_months": 34,
      "url_only_half_life": 5
    },
    {
      "cohort_year": 2024,
      "ever_scanned_base": 69922,
      "half_life_months": 6,
      "horizon_months": 22,
      "url_only_half_life": 5
    }
  ],
  "source": "Derived from cohort_survival_curves_incl_anon.csv (build signature-incl-anon-20260612).",
  "title": "Dynamic QR code half-life by creation cohort, platform-wide"
}