{
  "retrieved": "2026-10-20",
  "units": "Chained 2017 U.S. dollars; pre-1929 series backcast using Maddison growth",
  "historical_start": 1820,
  "last_historical_year": 2025,
  "estimate_year": 2026,
  "scenario_years": [
    2027,
    2050
  ],
  "bridge_year": 1929,
  "bridge_factor_bea_over_maddison": 0.8150871915990345,
  "bridge_formula": "GDP_pre1929 = MPD_GDP_year / MPD_GDP_1929 * BEA_GDP_1929",
  "estimate_formula": "GDP_2026 = BEA_GDP_2025 * (1 + IMF_real_growth_2026 / 100)",
  "imf_growth_2026_percent": 2.3,
  "imf_vintage": "October 2026",
  "scenario_formula": "GDP_y = estimated_GDP_2026 * 1.03 ** (y - 2026)",
  "scenario_status": "Authored illustrative assumption, not an institutional forecast or a causal estimate of AI",
  "sources": {
    "maddison": "https://ourworldindata.org/grapher/gdp-maddison-project-database?tab=chart&country=~USA",
    "bea": "https://fred.stlouisfed.org/series/GDPCA",
    "bea_csv": "https://fred.stlouisfed.org/graph/fredgraph.csv?id=GDPCA",
    "imf": "https://www.imf.org/external/datamapper/NGDP_RPCH@WEO/USA",
    "imf_api": "https://www.imf.org/external/datamapper/api/v1/NGDP_RPCH/USA",
    "reference_cbo": "https://www.cbo.gov/publication/62105",
    "reference_ai": "https://budgetmodel.wharton.upenn.edu/p/2025-09-08-the-projected-impact-of-generative-ai-on-future-productivity-growth/"
  },
  "visual_curve": {
    "type": "Editorial exponential-shaped visual metaphor",
    "scale": "Not to scale; no quantitative axes",
    "role": "Supporting line beneath large technological illustrations, rising at the far right",
    "coordinates": "Schematic, not mapped one-to-one from annual GDP",
    "benchmarks": [
      1820,
      1882,
      1946,
      1989,
      2026,
      2050
    ]
  }
}