The past few months have seen a flurry of reports on discouraging trends in life expectancy among some of the nation’s struggling populations. Different researchers have emphasized different groups and have tracked longevity trends over different time spans, but all have documented conspicuous differences between trends among more advantaged Americans compared with those in worse circumstances.

In a study published in April, Stanford economist Raj Chetty and his coauthors documented a striking rise in mortality rate differences between rich and poor. From 2001 to 2014, Americans who had incomes in the top 5 percent of the income distribution saw their life expectancy climb about 3 years. During the same 14-year span, people in the bottom 5 percent of the income distribution saw virtually no improvement at all.

Using different sources of information about family income and mortality, my colleagues and I found similar trends in mortality when Americans were ranked by their Social-Security-covered earnings in the middle of their careers. Over the three decades covered by our data, we found sizeable differences between the life expectancy gains enjoyed by high- and low-income Americans. For 50-year old women in the top one-tenth of the income distribution, we found that women born in 1940 could expect to live almost 6.5 years longer than women in the same position in the income distribution who were born in 1920. For 50-year old women in the bottom one-tenth of the income distribution, we found no improvement at all in life expectancy. Longevity trends among low-income men were more encouraging: Men at the bottom saw a small improvement in their life expectancy. Still, the life-expectancy gap between low-income and high-income men increased just as fast as it did between low- and high-income women.

One reason these studies should interest voters and policymakers is that they shed light on the fairness of programs that protect Americans’ living standards in old age. The new studies as well as some earlier ones show that mortality trends have tilted the returns that rich and poor contributors to Social Security can expect to obtain from their payroll tax contributions.

If life expectancy were the same for rich and poor contributors, the lifetime benefits workers could expect to receive from their contributions would depend solely on the formula that determines a worker’s monthly pensions. Social Security’s monthly benefit formula has always been heavily tilted in favor of low-wage contributors. They receive monthly checks that are a high percentage of the monthly wages they earn during their careers. In contrast, workers who earn well above-average wages collect monthly pensions that are a much lower percentage of their average career earnings.

The latest research findings suggest that growing mortality differences between rich and poor are partly or fully offsetting the redistributive tilt in Social Security’s benefit formula. Even though poorer workers still receive monthly pension checks that are a high percentage of their average career earnings, they can expect to receive benefits for a shorter period after they claim pensions compared with workers who earn higher wages. Because the gap between the life spans of rich and poor workers is increasing, affluent workers now enjoy a bigger advantage in the number of months they collect Social Security retirement benefits. This fact alone is enough to justify headlines about the growing life expectancy gap between rich and poor

There is another reason to pay attention to the longevity trends. The past 35 years have provided ample evidence the income gap between America’s rich and poor has widened. To be sure, some of the most widely cited income series overstate the extent of widening and understate the improvement in income received by middle- and low-income families. Nonetheless, the most reliable statistics show that families at the top have enjoyed faster income gains than the gains enjoyed by families in the middle and at the bottom. Income disparities have gone up fastest among working-age people who depend on wages to pay their families’ bills. Retirees have been better protected against the income and wealth losses that have hurt the living standards of less educated workers. The recent finding that life expectancy among low-income Americans has failed to improve is a compelling reason to believe the trend toward wider inequality is having profound impacts on the distribution of well-being in addition to its direct effect on family income.

Over the past century, we have become accustomed to seeing successive generations live longer than the generations that preceded them. This is not true every year, of course, nor is it always clear why the improvements in life expectancy have occurred. Still, it is reasonable to think that long-run improvements in average life spans have been linked to improvements in our income. With more money, we can afford more costly medical care, healthier diets, and better public health. Even Americans at the bottom of the income ladder have participated in these gains, as public health measures and broader access to health insurance permit them to benefit from improvements in knowledge. For the past three decades, however, improvements in average life spans at the bottom of the income distribution have been negligible. This finding suggests it is not just income that has grown starkly more unequal.

Editor's note: This piece originally appeared in Real Clear Markets.

As government funding for disability insurance is expected to run out next year, Congress should re-evaluate the costs of the program.

Nine million people in America today are receiving Social Security Disability Insurance, double the number in 1995 and six times the number in 1970. With statistics like that, it’s hardly surprising to see some in Congress worry that more will enroll in the program and costs would continue to rise, especially since government funding for disability insurance is expected to run out by the end of next year. If Congress does nothing, benefits would fall by 19% immediately following next year’s presidential election. So, Congress will likely do something. But what exactly should it do?

Funding for disability insurance has nearly run out of money before. Each time, Congress has simply increased the share of the Social Security payroll tax that goes for disability insurance. This time, however, many members of Congress oppose such a shift unless it is linked to changes that curb eligibility and promote return to work. They fear that rolls will keep growing and costs would keep rising, but findings from a report by a government panel conclude that disability insurance rolls have stopped rising and will likely shrink. The report, authored by a panel of the Social Security Advisory Board, is important in that many of the factors that caused disability insurance to rise, particularly during the Great Recession, have ended.

• Baby-boomers, who added to the rolls as they reached the disability-prone middle age years, are aging out of disability benefits and into retirement benefits. 


• The decades-long flood of women increased the pool of people with the work histories needed to be eligible for disability insurance. But women’s labor force participation has fallen a bit from pre-Great Recession peaks, and is not expected again to rise materially. 


• The Great Recession, which led many who lost jobs and couldn’t find work to apply for disability insurance, is over and applications are down. A recession as large as that of 2008 is improbable any time soon. 


• Approval rates by administrative law judges, who for many years were suspected of being too ready to approve applications, have been falling. Whatever the cause, this stringency augurs a fall in the disability insurance rolls.