For years, only a small portion of the people experiencing long spells of joblessness were college graduates. That’s starting to change.

The trend has alarmed some job-market watchers. “Such an increase is unprecedented outside of recessions,” said an economist at the Federal Reserve Bank of Richmond, alluding to a steady worsening of the long-term unemployment rate. Economists at Goldman Sachs recently expressed concern that a collapse in the number of job openings “risks locking out” those who are already unemployed.

By Noam Scheiber