Methodology

How the numbers were assembled, where they come from, and what to trust.

What this project is

Policy Playground is a static web application that lets a user assemble a policy package and watch the federal budget respond. It models four domains: the unified federal budget, the personal income tax, a hypothetical sovereign wealth fund, and household healthcare costs under different system architectures.

The defaults in each tool reflect a synthesized policy framework. The framework is not an attempt at neutrality. It is a coherent set of recommendations, anchored in mainstream economic evidence and assembled into a single document. The user can deviate from the default in any direction and the tools will recompute accordingly.

Nothing here is policy advice. Every quantitative claim is tied to a public source, and any number that comes from extrapolation or illustration is flagged in the user interface.

Data sources

Three sources do most of the work.

First, the Congressional Budget Office's Budget and Economic Outlook, 2026 to 2036 (February 2026) supplies the baseline. Revenue, outlays, deficit, debt held by the public, and GDP figures for fiscal year 2026 actuals and the 2036 projection all come from this report.

Second, the CBO's Options for Reducing the Deficit, 2025 to 2034 (December 2024) is the source for most individual lever scoring. The Committee for a Responsible Federal Budget restated these options to a 2026 to 2035 window so the math aligns with the current baseline. Per CRFB's note, savings in the 2025 to 2034 window would have been about 15 percent lower than what we use here.

Third, the Joint Committee on Taxation's tax expenditure tables (JCX-45-25, December 2025) supply scoring for tax-side reforms where CBO did not score a comparable option.

A small number of levers, particularly around a sovereign wealth fund, Singapore-style healthcare, and an AI windfall tax, have no analog in any official CBO or JCT publication. Those are clearly marked as illustrative estimates and are based on assumptions documented inside the lever itself.

Per-tool notes

Budget balancer

Ninety-one levers, covering revenue, spending, structural reforms, and transfer expansions. The default state of each lever matches the synthesized framework. Turning on the full default state produces about 3.0 percent of GDP in net deficit reduction over ten years, which is at the low end of the framework's stated 3 to 4 percent target range.

Levers below roughly fifty billion dollars over ten years were not included, because the tool would become noisy and the marginal contribution to any plan is small. The included levers represent about 95 percent of the deficit-reduction potential in the CBO catalog.

Some levers overlap. Eliminating the step-up basis at death and taxing capital gains as ordinary income above one million dollars both apply to top-bracket capital gains, for example. The tool sums them naively. A Treasury-grade score would haircut for interaction effects. The tool flags major overlaps in the lever detail panels.

Tax calculator

Uses 2025 federal tax brackets, standard deductions, and credit values. The reform side applies framework-consistent bracket adjustments, capital gains treatment, and expanded child tax credit. The calculation is shown line by line so the user can verify it. State income tax is approximated, not computed; the calculator's purpose is to illustrate federal effects.

Sovereign wealth fund

A discounted-cash-flow projection. Annual contribution, expected real return, and distribution rate are user-selectable. Defaults match the framework's Chapter 9 parameters. Comparisons to Norway's Government Pension Fund Global use the fund's published 2024 reports.

Healthcare comparison

Baseline household spending uses the Bureau of Labor Statistics Consumer Expenditure Survey and Kaiser Family Foundation premium data for the user's reported income and family size. The Singapore-style comparison uses the cost share assumptions from the framework's Chapter 8, including the government HSA contribution and catastrophic backstop. Every input and assumption is exposed.

Illustrative estimates

Twenty-six of the ninety-one budget levers carry an "illustrative estimate" tag. These fall into three groups.

The first group is framework-specific designs that CBO scored under different parameters. For example, the framework calls for a 45 percent top marginal rate with new top brackets; CBO scored a one-point rate change and a four-bracket expansion separately. The dollar figure shown in the tool is calibrated from CBO's scores but is not a direct CBO number.

The second group covers reforms with no CBO analog. The AI windfall tax, the sovereign wealth fund, the Singapore-style healthcare architecture, and an Operation Warp Speed for frontier technologies fall here. The tool's figures come from the framework itself and are explicitly speculative.

The third group is structural and growth-side levers. Federal zoning preemption, skilled immigration expansion, NEPA review caps, nuclear permitting reform, and similar reforms have effects that CBO has not scored in a directly applicable way. The tool uses calibrated figures based on academic estimates or analogous CBO scores.

The synthesized framework

The framework underlying the defaults is a long-form document covering taxation, social insurance, healthcare, defense, immigration, housing, energy, and the federal balance sheet. It draws from mainstream sources across the political spectrum and is the work of one author, with AI assistance in drafting and synthesis.

The framework PDF will be available for download here once it is converted from the source document.

Framework PDF: coming in v1 launch.

Limitations

The tools assume static behavioral response. A real Treasury or CBO score would model tax-elasticity-of-income, labor-supply effects, and macroeconomic feedback. Where those effects are large and well-documented, the tool notes them in the lever's counter-argument panel.

The baseline holds the OBBBA (Public Law 119-21, July 2025) law in place, including its expiring provisions. Some lever scoring assumes a continued expiring-provisions baseline, which is the CBO convention.

No state-level fiscal interactions are modeled. Medicaid lever scoring assumes the current federal matching structure.

Disclaimer

This site presents modeled estimates, not policy advice. Numbers flagged as illustrative are the author's calibrated estimates and do not represent any official score. The author has no affiliation with the Congressional Budget Office, the Joint Committee on Taxation, the Committee for a Responsible Federal Budget, or any political party or campaign.