Traditionally, U.S. labor markets have featured enormous turnover: Workers voluntarily leave jobs or are fired. Job changes vastly exceed net job creation, as hires often fill slots that someone else just left. On the whole, this has been a good thing, argues a new study. Workers can often find a better-paying job. But this “churning,” as the study calls it, is abating. Because employers are creating fewer net new jobs, workers won’t give up the ones they’ve got. As the labor market freezes up, the young lose bargaining power.

“Because job change accounts for a substantial portion of earnings growth, especially for younger workers, this decrease in churning reflects a decrease in workers’ opportunities for [higher wages],” write the study’s authors, economists John Haltiwanger of the University of Maryland and Henry Hyatt, Erika McEntarfer and Liliana Sousa of the Census Bureau.

The glut of job seekers depresses wages in a second way, argues the study. New firms — which create a disproportionate share of new jobs — don’t have to pay as much to hire. In 2001, workers at firms 10 years old or less earned 85 percent as much as workers at older firms. By 2011, they were paid only 70 percent as much. And these newer firms matter. From 1998 to 2011, they created 40 percent of net new jobs despite representing only 25 percent of total employment.