{
  "schemaVersion": "1.0.0",
  "asOf": "2026-08-26",
  "timeZone": "America/Puerto_Rico",
  "methodologyUrl": "https://lifedaysleft.com/methodology",
  "caveat": "Population-level illustrative estimate, not a prediction for any person. It does not account for individual health, sex, income, location, behavior, family history, or random events.",
  "model": {
    "name": "Life Days Left",
    "version": "Model 2026 · SSA 2026",
    "formula": "Arithmetic mean of Chetty male/female expected age at death at the 75th income percentile, shifted by the arithmetic-mean SSA male/female cohort-life-expectancy difference from 1967.",
    "parameters": {
      "chettyP75MaleExpectedAgeAtDeath": 83.785507,
      "chettyP75FemaleExpectedAgeAtDeath": 86.37175,
      "chettyP75ArithmeticMean": 85.0786285,
      "ssa1967ArithmeticMean": 78.3,
      "tropicalYearDays": 365.2425
    },
    "sources": [
      {
        "name": "Chetty et al., JAMA",
        "version": "2016",
        "url": "https://jamanetwork.com/journals/jama/fullarticle/2513561"
      },
      {
        "name": "SSA Trustees Report, Table V.A5 — Cohort Life Expectancy",
        "version": "2026 Intermediate",
        "url": "https://www.ssa.gov/oact/TR/2026/lr5a5.html"
      },
      {
        "name": "U.S. Census Bureau birth cohorts",
        "version": "2025 report",
        "url": "https://www.census.gov/newsroom/press-releases/2025/birth-cohorts-geographic-mobility-report.html"
      }
    ]
  },
  "generations": [
    {
      "generation": "Boomers",
      "birthRange": {
        "start": "1946-01-01",
        "end": "1964-12-31",
        "openEnded": false
      },
      "representativeBirthDate": "1955-01-01",
      "rangePercentLeft": {
        "oldest": 2,
        "youngest": 27
      },
      "representative": {
        "daysLeft": 4283,
        "percentLeft": 14
      }
    },
    {
      "generation": "Gen X",
      "birthRange": {
        "start": "1965-01-01",
        "end": "1980-12-31",
        "openEnded": false
      },
      "representativeBirthDate": "1972-07-01",
      "rangePercentLeft": {
        "oldest": 27,
        "youngest": 47
      },
      "representative": {
        "daysLeft": 11606,
        "percentLeft": 37
      }
    },
    {
      "generation": "Millennials",
      "birthRange": {
        "start": "1981-01-01",
        "end": "1996-12-31",
        "openEnded": false
      },
      "representativeBirthDate": "1988-07-01",
      "rangePercentLeft": {
        "oldest": 48,
        "youngest": 67
      },
      "representative": {
        "daysLeft": 18107,
        "percentLeft": 57
      }
    },
    {
      "generation": "Gen Z",
      "birthRange": {
        "start": "1997-01-01",
        "end": "2012-12-31",
        "openEnded": false
      },
      "representativeBirthDate": "2004-07-01",
      "rangePercentLeft": {
        "oldest": 67,
        "youngest": 85
      },
      "representative": {
        "daysLeft": 24554,
        "percentLeft": 75
      }
    },
    {
      "generation": "Alpha",
      "birthRange": {
        "start": "2013-01-01",
        "end": "2026-08-26",
        "openEnded": true
      },
      "representativeBirthDate": "2019-07-01",
      "rangePercentLeft": {
        "oldest": 85,
        "youngest": 100
      },
      "representative": {
        "daysLeft": 30488,
        "percentLeft": 92
      }
    }
  ]
}