Not only do unmarried women account for a third of households aged 65–69 and two thirds of households aged 85 and older, many court poverty thanks to caregiving interruptions weighing on pay and work records.

One study, the report notes, “found that women ages 65–74 who spent at least 10 years as a single mother were 55 percent more likely to be poor than continuously married mothers of similar education and ethnicity.”

While caregiving programs in other countries vary because of differing objectives, the study looked at programs in the U.K., Sweden and Germany. In Germany and the U.K., caregiver credits are offered for taking care of elderly or ill relatives as well as children, while Sweden confines them to those who take care of children—but in Sweden parents must also have work credits.

In the U.S., it's been suggested that the number of work years excluded from determining benefits be increased, and credits be provided to parents with a child under age six for up to five years. The former would cost relatively little, while the latter would “have a more significant cost.”

The report points out that childcare credits were found in a couple of studies to have modest effects, but would be most helpful to women at the bottom of the lifetime earnings distribution, and in another were found to “be more effective than either current spousal benefits or dropout years at reducing poverty for low-income groups and minorities.”

Costs, the report concludes, could be covered by reducing benefits somewhat for higher earners.