But Maestas cautions that the projections are based on historical trends and may not be accurate predictions. Her guess is that productivity has fallen as the population ages because the most skilled and experienced people have left in larger numbers, since they’re more successful and wealthier and can afford to retire. If she’s right, then it’s not that workers become less productive as they age, but that the most productive ones stop working.

This means, Maestas says, that a big drop in productivity isn’t inevitable. New technologies and business policies might keep talented people working longer. (Less happily, so might shrinking savings and disappearing retirement plans.) Teams made of both young and old people, with diverse experiences, might even be more productive. “Are we all getting less productive, and we’re stuck with that?” she says. “Not necessarily.”

“Despite all the stressing about aging,” says Daron Acemoglu, an MIT economist, “there is surprisingly very little evidence that aging societies are worse economically.” Looking at GDP data from 1990 to 2015, Acemoglu and Boston University’s Pascual Restrepo found no correlation between aging demographics and slowed economic growth. In fact, countries like South Korea, Japan, and Germany, all with rapidly aging populations, are actually doing well.