Projection Methodology

We use the Modeling Income in the Near Term, Version 8 (MINT8) microsimulation model to make all projections related to beneficiaries and taxpayers on this website. SSA's Office of the Chief Actuary makes Trust Fund solvency projections. MINT8 is built from Social Security's administrative records matched to the Survey of Income and Program Participation (SIPP) and uses economic, demographic, and programmatic assumptions in the 2019 Trustees Report for its projections. We use the model for projections in:

For more information on the latest model methodology, see the Urban Institute's MINT8 final report.
(Note: The report is based on the 2018 Trustees Report, while our projections are updated with the 2019 Trustees Report assumptions.)

MINT8 made several improvements to MINT7, including updating administrative data (to 2015) and Trustees Report assumptions (to 2019), updating Social Security claiming and retirement estimates, adding same-sex marriage projections, improving accounting of the Great Recession's effects, improving supplemental poverty calculations, and improving noncovered pension estimates for calculating the Windfall Elimination Provision and Government Pension Offset.

MINT Program Rules

There are many Social Security program rules and they are often complicated. The MINT model includes most of the current-law basic rules, including:

  • Average indexed monthly earnings (AIME),
  • Primary insurance amount (PIA),
  • Special minimum PIA,
  • Windfall Elimination Provision (WEP),
  • Cost-of-living adjustment (COLA),
  • Early retirement reduction factors and delayed retirement credits (DRCs),
  • Spousal and divorced spousal benefits,
  • Surviving spouse and divorced surviving spousal benefits,
  • Independent entitlement for divorced spousal benefits,
  • Widow's limit,
  • Child benefits,
  • Child-in-care spousal benefits,
  • Government Pension Offset (GPO),
  • Family maximum and disability family maximum,
  • Retirement earnings test (RET), and
  • Lump sum death payment (LSDP).

MINT projects Supplemental Security Income (SSI)–related information and includes SSI payments as part of the household income calculation. However, the SSI projections are less robust than the Social Security benefit projections because SSI is more complicated and only part of the SSI rules are included in MINT.

The following Social Security and SSI rules are not included in the MINT model:

  • Benefit rules from before 1979: For example, earlier PIA formulas or special benefits that no longer exist.
  • Monthly benefit adjustments: MINT only has annual earnings and income amounts, so monthly benefit rules, such as the earnings test, are calculated on an annual basis.
  • Complicated claiming situations: MINT projects a single claiming age and does not have multiple claiming ages for an individual if he or she becomes eligible for different benefits. It also does not allow for sophisticated claiming strategies (e.g., withdrawal of application).
  • Disability administration and adjudication: MINT does not output projections of the diagnostic group for the disability, whether the initial claim was denied, how long it takes to appeal and receive benefits, etc. In our projections, disability benefits are paid from the onset date until death or conversion to retired-worker benefits. While the MINT model projects up to three disability spells, our benefit calculator is not structured to handle them.
  • Disability return-to-work rules: Including the trial work period, extended period of eligibility, and continuing disability reviews (CDRs).
  • Return to work initiatives: For example, Ticket to Work, Benefit Offset National Demonstration (BOND), Work Incentives and Planning Assistance (WIPA).
  • Dependent parents: MINT does not include information on parents.
  • Disabled adult children (DACs): MINT flags respondents who may be (DACs) but cannot calculate those benefits because it does not have earnings and disability status for the worker and the adult child (children are ineligible if they can receive their own disabled worker benefit).
  • Benefit taxation: Although the MINT model has income tax projections, the benefits and income shown for baselines and policy options/proposals are pre-tax, and no Medicare premiums are subtracted.
  • Representative payees: MINT does not have any information needed to model beneficiaries' representative payees.
  • SSI state supplements: These are not included because SIPP is a nationally representative survey.

Scheduled Benefits and Payable Benefits

Scheduled benefits are those promised under current-law benefit formulas and rules.

Payable benefits are those that can be paid while maintaining program solvency according to projected Trust Fund balances. Payable benefits are an across-the-board reduction of final scheduled benefit amounts, not AIME or PIA. These reductions would begin with Trust Fund exhaustion in 2035 (based on the 2019 Trustees Report assumptions) and be 20.0 percent in 2050 and 23.8 percent in 2070.

Payable benefits are no longer included in tables showing the projected effects of the policy options/proposals, but are available upon request. In discussions with policymakers, stakeholders, and users at the Social Security Advisory Board's May 2019 MINT model forum, there was agreement that payable benefits analyses added confusion given the already complex current-law rules; non-intuitive distributional effects; and the sheer amount of results for benefits, taxes, replacement rates, and lifetime benefit to tax ratios.

Notes, Caveats, and Limitations

Child benefitsMINT does not know which parent, if either, the child is living with, if the parents are not married when the child is eligible for child benefits. However, MINT assumes a sole parent if unmarried at the time the child is born, or the mother if the parents divorce after the child is born.

WEP and GPO—These rules reduce Social Security benefits when there is a pension from noncovered employment. MINT8 estimates the value of those noncovered pensions, but the actual values of covered versus noncovered pensions received are unknown. The estimates of noncovered pensions are based on actual noncovered earnings amounts from 1982 onward.

Policy option/proposal tables—The following notes apply specifically to the policy option/proposal tables:

  • We model a policy option/proposal by adding the option's changes to the legislated benefit formulas so that comparing the option to current law isolates the option's effects.
  • A small percentage of beneficiaries will receive a benefit reduction under a policy option/proposal intended to increase benefits and vice versa. These counterintuitive results happen because of interactions with program rules such as the retirement earnings test, the family maximum, and dual entitlement.