{
  "generated_at": "2026-06-02",
  "engine": "roth-gap-mc-1.0.0",
  "method": "Deterministic year-by-year federal income tax simulation (2025 MFJ brackets, standard deduction, IRS Uniform Lifetime Table RMDs from age 73, simplified up-to-85% Social Security taxation), comparing a do-nothing Traditional-IRA strategy vs filling the 12% bracket with Roth conversions in the gap years (retirement age 65 to RMD age 73); Monte Carlo overlay on real return (20,000 paths) for the distribution",
  "assumptions": {
    "filing_status": "Married Filing Jointly",
    "tax_year_law": "2025 (IRS Rev. Proc. 2024-40), held constant in real dollars",
    "retire_age": 65,
    "rmd_age": 73,
    "plan_to_death_age": 90,
    "ss_start_age": 67,
    "ss_annual_real": 36000.0,
    "conversion_target": "top of 12% federal bracket (MFJ)",
    "gross_return_mean_real": 0.05,
    "gross_return_vol": 0.1,
    "n_paths": 20000,
    "seed": 20260602,
    "std_deduction_mfj_2025": 30000.0,
    "top_of_12_bracket_mfj_2025": 96950.0
  },
  "headline": {
    "ira_balance": 1000000,
    "median_lifetime_saving": 31741,
    "mean_lifetime_saving": 49737,
    "pct_paths_conversion_wins": 69.5,
    "median_tax_do_nothing": 160507,
    "median_tax_convert": 129648,
    "saving_2m_ira": 112795
  },
  "deterministic_check_flat_5pct": {
    "ira_balance": 1000000,
    "tax_do_nothing": 171531,
    "tax_convert": 129648,
    "lifetime_saving": 41883
  },
  "results": [
    {
      "ira_balance": 500000,
      "median_tax_do_nothing": 47896,
      "median_tax_convert": 58945,
      "median_lifetime_saving": -12939,
      "mean_lifetime_saving": -4808,
      "p25_saving": -39551,
      "p75_saving": 20207,
      "pct_paths_conversion_wins": 39.3
    },
    {
      "ira_balance": 1000000,
      "median_tax_do_nothing": 160507,
      "median_tax_convert": 129648,
      "median_lifetime_saving": 31741,
      "mean_lifetime_saving": 49737,
      "p25_saving": -9064,
      "p75_saving": 91958,
      "pct_paths_conversion_wins": 69.5
    },
    {
      "ira_balance": 1500000,
      "median_tax_do_nothing": 282846,
      "median_tax_convert": 208372,
      "median_lifetime_saving": 74832,
      "mean_lifetime_saving": 100292,
      "p25_saving": 27049,
      "p75_saving": 148727,
      "pct_paths_conversion_wins": 91.2
    },
    {
      "ira_balance": 2000000,
      "median_tax_do_nothing": 430096,
      "median_tax_convert": 314183,
      "median_lifetime_saving": 112795,
      "mean_lifetime_saving": 129060,
      "p25_saving": 41294,
      "p75_saving": 191396,
      "pct_paths_conversion_wins": 88.8
    }
  ]
}