Sources

The 29 data files, official publications and documents behind every number in the simulator. Generated from SOURCES.md; data built 2026-09-27.

Every number in the simulator comes from one of the files below. Raw copies are in data/raw/, except the Census IMDB zip files, which are about 900 MB.

  1. IRS SOI, Publication 1304 (Individual Complete Report), Table 1.2, "All returns: AGI, exemptions, deductions and tax items, by size of AGI and marital status" (released March 2026)

    Period
    Tax year 2023
    Used for
    Returns, AGI, itemized and standard deductions, taxable income, income tax after credits, by 19 AGI ranges × 4 filing statuses
    File / URL
    23in12ms.xls, https://www.irs.gov/statistics/soi-tax-stats-individual-statistical-tables-by-size-of-adjusted-gross-income

  2. IRS SOI Pub. 1304 Table 3.3, "Tax liability, tax credits and tax payments"

    Period
    TY2023
    Used for
    Total credits and net investment income tax by AGI range; national totals
    File / URL
    23in33ar.xls

  3. IRS SOI Pub. 1304 Table 3.5, "Tax generated, by rate and size of AGI"

    Period
    TY2023
    Used for
    Preferential (capital gain/dividend) income by AGI; validates tax generated by AGI
    File / URL
    23in35tr.xls

  4. IRS SOI Pub. 1304 Table 3.6, "Income taxed at each rate, by filing status"

    Period
    TY2023
    Used for
    Preferential income by filing status; validates income taxed at each rate and tax by status
    File / URL
    23in36tr.xls

  5. IRS SOI Pub. 1304 Table 3.4, "Tax classified by highest marginal rate" (reference only)

    Period
    TY2023
    Used for
    Cross-check
    File / URL
    23in34tr.xls

  6. IRS SOI Table 4.3, "Returns by top descending cumulative percentiles"

    Period
    TY2023
    Used for
    Top-tail knots ($16.09M = top 0.01% floor, $78.62M = top 0.001% floor); validates top tax shares
    File / URL
    23in43ts.xls, https://www.irs.gov/statistics/soi-tax-stats-individual-income-tax-rates-and-tax-shares

  7. IRS SOI Pub. 1304 Table 1.2

    Period
    TY2017
    Used for
    Personal exemptions per return (exemption amount ÷ $4,050) for the exemption slider and pre-2018 preset; dependents per return (exemptions − filers) to split CTC claimers across filing statuses
    File / URL
    17in12ms.xls

  8. IRS Rev. Proc. 2022-38

    Period
    2023
    Used for
    Current-law brackets, standard deductions, 0/15/20% capital gain thresholds
    File / URL
    rp-22-38.pdf

  9. IRS Rev. Proc. 2016-55

    Period
    2017
    Used for
    Pre-2018 brackets, standard deductions, $4,050 exemption
    File / URL
    rp-16-55.pdf

  10. BLS CPI-U all items, annual average (FRED series CPIAUCNS)

    Period
    2017 = 245.120, 2023 = 304.702
    Used for
    Inflating 2017 parameters (×1.2431)
    File / URL
    fred_cpiaucns_annual.csv

  11. U.S. Census Bureau, Merchandise Trade Imports (IMDB) monthly files IMDB2507, IMDB2512, IMDB2602, IMDB2607 (IMP_COMM.TXT + CONCORD.TXT)

    Period
    CY2025; Mar–Jul 2026
    Used for
    Imports for consumption and calculated duty by HTS-10, grouped into 12 end-use categories
    File / URL
    https://www.census.gov/foreign-trade/data/dataproducts.html → data/tariff_categories.json

  12. U.S. Treasury, Monthly Treasury Statement Table 4, via the Fiscal Data API

    Period
    Jan 2025–Aug 2026; FY2024, FY2025
    Used for
    Customs duties (gross, refunds, net), excise total, individual income tax receipts
    File / URL
    mts4_customs.json, mts4_fy2024.json, mts4_fy2025.json

  13. IRS SOI Historical Table 20, "Federal excise taxes reported to or collected by IRS, TTB and Customs, by type of tax"

    Period
    FY2024
    Used for
    Excise receipts by type
    File / URL
    histab20.xlsx, https://www.irs.gov/statistics/soi-tax-stats-excise-tax-statistics

  14. IRS Form 720 (Rev. June 2026)

    Period
    current
    Used for
    Fuel rates: gasoline $0.184/gal; diesel and kerosene $0.244/gal; 12% heavy-truck retail tax
    File / URL
    f720.pdf

  15. TTB, Tax and Fee Rates

    Period
    current
    Used for
    Spirits $13.50/proof gal, beer $18/bbl, wine rates, cigarettes $50.33/1,000, firearms 10%/11%
    File / URL
    ttb_rates.html

  16. 26 U.S.C. §4261, §4051, §4501 (Cornell LII)

    Period
    current
    Used for
    7.5% air ticket tax, 12% truck tax, 1% stock buyback tax
    File / URL
    law.cornell.edu

  17. EIA retail gasoline (all grades) and No. 2 diesel prices, annual

    Period
    2024: $3.424, $3.760
    Used for
    Price level for the excise elasticity on fuels
    File / URL
    EMM_EPM0_PTE_NUS_DPGa.xls, EMD_EPD2D_PTE_NUS_DPGa.xls

  18. Covington & Burling, "IEEPA Tariffs Terminated, Replacement Section 122 Tariffs Take Effect" (Feb 2026)

    Period
    2026
    Used for
    Context: SCOTUS Learning Resources v. Trump (Feb 20, 2026); 10% Section 122 surcharge Feb 24–Jul 24, 2026
    File / URL
    cov.com

  19. IRS SOI Pub. 1304 Table 3.3 (same file as #2), CTC columns

    Period
    TY2023
    Used for
    By AGI range: nonrefundable CTC/ODC returns & amount (cols 12/13: 38.95M, $84.42B), refundable CTC/ACTC (38/39: 17.63M, $34.53B), ACTC used against income tax (52/53: $0.33B), against other taxes (90/91: $2.13B), refunded portion (118/119: $32.06B)
    File / URL
    23in33ar.xls

  20. IRS SOI Publication 4801, Individual Income Tax Returns Line Item Estimates (Rev. 6-2026)

    Period
    TY2023
    Used for
    Schedule 8812: 63.788M qualifying children (37.45M returns), 21.154M other dependents (16.95M returns), line 12 returns 46.69M, line 14 returns 38.62M, line 27 returns 17.40M; 47.8M Schedule 8812s
    File / URL
    p4801.pdf, https://www.irs.gov/pub/irs-pdf/p4801.pdf

  21. IRS SOI Pub. 1304 Table 1.4, "Sources of income, adjustments and tax items"

    Period
    TY2023
    Used for
    Wages and business net income ÷ AGI by range (earned income for the ACTC)
    File / URL
    23in14ar.xls

  22. IRS Instructions for Schedule 8812 (2023) and the 2023 Schedule 8812 reproduced in Pub. 4801

    Period
    2023
    Used for
    $2,000/child, $500/other dependent, $200k/$400k phase-out at 5%, refundable max $1,600/child, 15% of earned income over $2,500
    File / URL
    irs_ctc_2023_8812instr.pdf, https://www.irs.gov/pub/irs-prior/i1040s8--2023.pdf

  23. IRS, "2021 Child Tax Credit and Advance Child Tax Credit Payments — Topic C" and Instructions for Schedule 8812 (2021)

    Period
    2021
    Used for
    ARPA preset: $3,600 under 6 / $3,000 ages 6–17, children under 18, first phase-out $75k/$112.5k/$150k, second $200k/$400k, $50 per $1,000, fully refundable for residents, ODC unchanged
    File / URL
    irs_2021ctc_topicC.html, i1040s8--2021.pdf

  24. IRS Publication 972 (2017)

    Period
    2017
    Used for
    Pre-2018 CTC: $1,000/child, phase-out $75k single/HoH, $110k MFJ, $55k MFS, 15% of earned income over $3,000
    File / URL
    p972--2017.pdf, https://www.irs.gov/pub/irs-prior/p972--2017.pdf

  25. U.S. Census Bureau, CPS ASEC 2023, America's Families and Living Arrangements, Table F1

    Period
    2023
    Used for
    Family households by number of members under 18: 1 = 15,751K, 2 = 13,213K, 3+ = 7,478K
    File / URL
    cps2023_tabf1-all.xls, https://www2.census.gov/programs-surveys/demo/tables/families/2023/cps-2023/tabf1-all.xls

  26. U.S. Census Bureau, Vintage 2024 national population estimates by single year of age and sex

    Period
    July 1, 2023
    Used for
    Ages 0–5 = 22.56M, 0–16 = 68.84M, 17 = 4.42M (under-6 share, 17-year-old factor for the 2021 preset)
    File / URL
    nc-est2024-agesex-res.csv

  27. U.S. Census Bureau, P60-282, "Income in the United States: 2023" (Guzman & Kollar, Sept 2024), Table A-1 and Table A-2 (CPS ASEC 2024)

    Period
    Calendar 2023
    Used for
    Income context reference line: median household income $80,610 (90% MOE ±634), 132,200K households (shown as 132.2M), mean household income $114,500 (±1,098)
    File / URL
    p60-282.pdf, https://www.census.gov/library/publications/2024/demo/p60-282.html

  28. IRS SOI Pub. 1304 Table 1.2 (same file as #1), All-returns rows

    Period
    TY2023
    Used for
    Income context cross-check: mean AGI = total AGI ÷ number of returns, mean taxable income = total TI ÷ returns, for all filers and each status. The model's median AGI and TI are interpolated within Table 1.2's 19 AGI ranges
    File / URL
    23in12ms.xls

  29. IRS SOI Table 4.3 (same file as #6), top 1% row

    Period
    TY2023
    Used for
    README cross-check for the ⓘ note: top 1% share of AGI 20.63% (SOI, non-dependent returns) vs 20.9% in the model
    File / URL
    23in43ts.xls

Not used (and why): PolicyEngine Enhanced CPS and taxcalc cps.csv. The SOI-cell approach met the calibration target on its own, so neither was needed.