The discount rate in a present value damages calculation is the assumed rate of return a plaintiff will earn by investing a lump-sum award, and it controls how large that award has to be to cover future losses. A higher rate shrinks the award; a lower rate enlarges it. The U.S. Supreme Court has flagged real (inflation-adjusted) rates between one and three percent as a reasonable range, but the actual figure in any case turns on the method used, the jurisdiction, and which expert the factfinder believes.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983)
Why the Rate Matters So Much
The concept rests on the time value of money. A dollar today can be invested and grown, so a dollar promised ten years from now is worth less than a dollar in hand. When a court converts a stream of future losses into one check at judgment, the discount rate is the assumed growth rate that makes the math work. Higher assumed growth means the plaintiff needs less money up front. Lower assumed growth means the court has to hand over more.
That inverse relationship is why both sides fight so hard over a number that looks trivially small. Take a plaintiff expected to lose $80,000 per year in earnings for 25 years. At a two-percent discount rate, the present value of that stream is roughly $1.56 million. At four percent, it drops to about $1.25 million. A two-point gap cost the plaintiff over $300,000, and no one changed a single fact about the injury or the salary. The entire difference came from an assumption about how well the plaintiff would invest.
The Three Main Methods Economists Use
Forensic economists generally pick one of three approaches. Each makes different assumptions about inflation, investment returns, and how much market risk the injured party should carry. In Jones & Laughlin Steel Corp. v. Pfeifer, the Supreme Court surveyed all three and refused to mandate any of them for federal courts, leaving the choice to the trial judge as long as the reasoning is explained.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983)
The Real Interest Rate Method
This approach strips inflation out of both sides of the equation. Instead of projecting nominal wage growth and then discounting at a nominal interest rate, the economist calculates the real rate of return, which is how much money grows in purchasing power after inflation. If a Treasury bond pays four percent and inflation runs at three, the real discount rate is roughly one percent.
The Pfeifer Court said a trial court using this approach should not be reversed if it selects a rate between one and three percent and explains its choice.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983) The method is popular because it avoids the notoriously hard job of predicting future inflation and future interest rates as separate variables. Treasury Inflation-Protected Securities have made it even more practical, since TIPS yields are a market-derived real rate you can observe directly.
The Total Offset Method
Here the assumption is that wage growth and investment returns roughly cancel each other out. If your salary would have grown at three percent per year and you can invest at three percent per year, the two forces offset, and the court simply awards the undiscounted total. No expert testimony about interest rate forecasts is required, which makes trials cheaper and faster.
The Pfeifer Court declined to impose this method on unwilling parties, finding insufficient data to conclude that national wage-growth patterns reliably mirror investment returns across every industry.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983) Some jurisdictions still accept it. Because no reduction is applied to the future loss stream, total-offset awards tend to be larger, and the method spares plaintiffs the risk that investment returns fail to keep pace with rising costs.
The Market-Based Portfolio Approach
This method assumes the plaintiff will invest the award in a diversified mix of stocks and bonds rather than parking it in safe government securities. Diversified portfolios historically return more than Treasuries, so the discount rate is higher and the present value comes out lower. Defense experts favor it for exactly that reason.
The main objection is fairness. An injured person did not choose to become an investor, and a portfolio approach effectively forces them to bear market risk to fund their own recovery. If the stock market drops 30 percent two years after judgment, the medical bills do not drop with it. That concern is why most forensic economists build discount rates around lower-risk government securities. A survey of National Association of Forensic Economics members found that 82 percent used only U.S. government securities for discounting.2Marquette University ePublications. Risk, Discounting, and the Present Value of Future Earnings
The Net Discount Rate
In practice, many economists collapse the discount rate and the earnings-growth rate into a single figure called the net discount rate. Instead of separately forecasting how fast wages grow and how fast the award earns returns, this method uses the gap between the two. If wages grow at three percent and safe investments return four percent, the net discount rate is roughly one percent, and the entire calculation runs off that combined number.
The advantage is stability. Research in forensic economics has shown that even when nominal interest rates and wage-growth rates jump around from year to year, the gap between them tends to stay relatively steady over long periods. That makes the net discount rate a more reliable forecasting tool than either component alone, and it reduces the chance that a temporary spike in rates or a recession-year wage dip will distort an award meant to cover decades of losses.
Medical Costs Need Their Own Inflation Track
General consumer inflation and medical inflation are not the same thing. Between 2000 and 2024, medical care prices rose roughly 121 percent while overall consumer prices rose about 86 percent. Within medical care, the disparity is starker for certain categories: hospital services and nursing home costs have recently climbed at annual rates of six to seven percent, while physician services barely moved.
This matters because the discount rate has to be paired with the correct inflation assumption. If an economist uses general CPI to project the future cost of a spinal-cord-injury patient’s lifetime nursing care and then discounts at a Treasury rate, the award will fall short. The cost of that care is rising faster than general prices, so the inflation side of the equation has to reflect medical-specific data. On cases with significant future medical costs, forensic economists will often calculate a separate net discount rate using the medical component of the CPI rather than the general index.
How Long the Losses Are Assumed to Last
The discount rate tells you how much to reduce each future dollar. The duration tells you how many future dollars to reduce. Getting the time horizon wrong can distort an award just as badly as picking the wrong rate.
Life Expectancy for Medical and Care Costs
Future medical expenses typically run to the plaintiff’s expected date of death. Courts and experts commonly rely on actuarial life tables published by the Social Security Administration, which give average remaining years of life at any age based on current mortality data.3Social Security Administration. Actuarial Life Table Those tables reflect population-wide averages. When the injury itself reduces life expectancy, expert medical testimony adjusts the figure downward. That creates a tension juries sometimes struggle with, since the defendant’s wrongful act shortened the plaintiff’s life and the defendant then argues for a smaller award because of it.
Work-Life Expectancy for Lost Earnings
Lost-wage calculations use a shorter horizon than medical costs, because people do not work until they die. Forensic economists estimate work-life expectancy, which factors in mortality plus the probability of disability, unemployment, and voluntary withdrawal from the labor force. Bureau of Labor Statistics data on labor force participation and Social Security Administration data on disability incidence feed the models. The result is typically well short of life expectancy. A 35-year-old plaintiff might have a life expectancy of 45 more years but a work-life expectancy of only 27, and the lost-earnings calculation runs to the shorter number.
The Tax Wrinkle in the Rate
Damages received for personal physical injuries or physical sickness are excluded from gross income under federal tax law.4Office of the Law Revision Counsel. 26 USC 104 – Compensation for Injuries or Sickness The award arrives tax-free whether it comes as a lump sum or periodic payments. But investment earnings on the lump sum are fully taxable. Once the plaintiff deposits the check and starts earning interest or dividends, those returns are ordinary income subject to federal and state tax.
That creates a mismatch. The discount rate assumes a certain return, but after taxes the plaintiff keeps less. If the economist uses a four-percent nominal discount rate and the plaintiff’s effective tax rate on investment income is 25 percent, the real after-tax return is closer to three percent. Using the pre-tax rate produces a smaller award than the plaintiff actually needs to be made whole. Some courts require after-tax discount rates; others leave it to expert testimony. The Pfeifer Court specifically referenced “the after-tax market interest rate” as the appropriate discount rate when future earnings are projected in nominal terms.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983)
Structured settlement annuities sidestep the tax problem. Under the same code provision, periodic payments from a structured settlement for personal physical injuries stay tax-free, including the investment growth built into the annuity’s payment schedule.4Office of the Law Revision Counsel. 26 USC 104 – Compensation for Injuries or Sickness A structured settlement effectively delivers a higher after-tax return than a lump sum invested at the same rate, because the plaintiff never owes tax on the earnings. When a defendant offers a structured settlement, the annuity pricing implicitly uses the insurance company’s own discount rate, which may differ substantially from what a forensic economist would select for a lump-sum calculation.
The Legal Rules That Constrain the Rate
Courts do not give economists a blank canvas. Several layers of legal rules limit which methods and rates are permissible.
The Pfeifer Framework in Federal Court
Jones & Laughlin Steel Corp. v. Pfeifer remains the leading federal authority. The Court refused to pick a winner among the three methods, but set two guardrails. First, the discount rate has to be chosen on the same basis as the earnings projection: real rate for real projections, nominal rate for nominal projections. Mixing them produces nonsense. Second, the trial court has to make a “deliberate choice” of rate and explain its reasoning rather than blindly apply a state-law default.1Justia Law. Jones and Laughlin Steel Corp. v. Pfeifer, 462 U.S. 523 (1983)
Statutory Discount Rates
Some states bypass the debate by fixing a discount rate in their civil procedure codes. The statute mandates a specific percentage that courts must apply to future damage awards above a threshold. The advantage is predictability for insurers and defendants setting reserves. The disadvantage is that a rate set by the legislature years ago may bear no resemblance to current market conditions. When Treasury yields sat near historic lows in the early 2020s, plaintiffs in fixed-rate jurisdictions sometimes had their awards discounted at rates far above what any safe investment could actually deliver.
Expert Admissibility Under Rule 702 and Daubert
In federal court and most states that follow the same framework, a forensic economist’s discount-rate opinion has to survive a gatekeeping review before it reaches the jury. Federal Rule of Evidence 702 requires the proponent to show it is “more likely than not” that the testimony rests on sufficient facts, reliable methods, and a sound application of those methods to the case.5United States Courts. Federal Rules of Evidence The judge evaluates whether the methodology has been tested, subjected to peer review, and accepted within the forensic economics community.6Legal Information Institute (LII). Daubert Standard
In practice, an expert who cherry-picks an unusually high or low discount rate without grounding it in recognized data sources risks having the entire testimony excluded before trial. The 2023 amendment to Rule 702 tightened this standard by adding the “more likely than not” language, making it harder for either side to slip unreliable opinions past the judge.
Where Current Rates Sit
As of early 2025, the 10-year U.S. Treasury yield sat around 4.45 percent.7U.S. Department of the Treasury. Daily Treasury Par Yield Curve Rates That nominal rate is relevant for economists using a nominal approach but overstates the real return. TIPS yields, which strip out expected inflation, provide a direct read on the real risk-free rate and have recently hovered between 1.5 and 2.5 percent, squarely within the range the Supreme Court flagged in Pfeifer decades ago.
Timing matters. A case resolved during a period of unusually high or low yields can lock in a rate that looks strange five years later. Some economists address this by using historical averages instead of a snapshot, arguing that a long-term average better reflects what a plaintiff will actually earn over a 20- or 30-year payout horizon. Others insist that today’s yield curve is the only honest measure of what the market offers right now. One study in the forensic economics literature found that discounting a 30-year loss stream using the current Treasury yield curve produced a present value nearly 20 percent higher than discounting at a constant rate based on historical averages.2Marquette University ePublications. Risk, Discounting, and the Present Value of Future Earnings
Whichever method the expert uses, the discount rate is not pulled from the air. It is built from observable market data, constrained by legal precedent, and tested against the specific facts of the injury and the expected future costs. When the other side’s economist offers a dramatically different figure, the first question is whether they matched the discount rate to the same inflation and growth assumptions used to project the losses. If the two sides of the equation were built on different foundations, the math does not hold up.