Roughly half of college graduates end up in jobs where their degrees aren’t needed‚ and that underemployment has lasting implications for workers’ earnings and career paths. That is the key finding of a new study tracking the career paths of more than 10 million people who entered the job market over the past decade. It suggests that the number of graduates in jobs that don’t make use of their skills or credentials—52%—is greater than previously thought‚ and underscores the lasting...