Jow Amer hammers slabs out of a boulder in Lyons, Colo., in September. Less than 8 percent of rock splitters in quarries have a bachelor's degree or higher, according to 2015-2016 figures from the Labor Department. (Kevin J. Beaty/Denverite/AP)

Federal Reserve Bank of New York economist Gizem Kosar may not have cracked the Case of the Missing Wage Growth yet, but she has found a promising lead.

In the July release of labor market data from the bank’s Survey of Consumer Expectations, Kosar and analyst Kyle Smith noticed something surprising: Workers without a bachelor’s degree are switching jobs at the highest rate since the thrice-yearly survey began in 2014, but their salaries have fallen slightly in the past year.

(Andrew Van Dam/Andrew Van Dam)

Their earnings should be rising. If less-educated workers are in demand, employers should be forced to lift wages to poach outsiders and retain their employees in the face of rival offers. That has started to happen for workers with bachelor’s or advanced degrees.

During the labor market’s nine-year crawl back from the Great Recession, employers grew accustomed to a seemingly endless supply of experienced, educated Americans who were desperate for work.

Now, the market is heating up. The unemployment rate for workers 25 and older with at least a bachelor’s degree sat at 2.0 percent in September. It has hovered around that number for a year and doesn’t have much more room to fall.

(Andrew Van Dam/Andrew Van Dam)

As competition for their services intensifies, the average full-time salary for college-educated workers in the survey rose about $5,800 over the past year. Over the same time, the comparable salary for less-educated workers in the survey has declined by about $4,700.

Those trends raise another question: Why are less-educated workers switching jobs? It’s apparently not because they’re chasing the money.

Here, the New York Fed survey’s utility becomes clear. It follows a rotating, representative panel of about 1,000 U.S. households and asks questions about worker motivations and job satisfaction that we can’t get from our usual sources. Because it follows workers for a year, the survey can provide additional insight into things such as job-switching and earnings growth.

Supplemental surveys like this one won’t beat the Labor Department at its own game. They won’t produce Unemployment Rate 2.0. But when done right, they fill in gaps and suggest answers to some of the job market’s more bewildering mysteries.

The first clue is that employers are being forced to cast a wider net. Poaching a college-educated worker is costly and, thanks to that salary surge, getting more so. On average, respondents with a bachelor’s degree or higher said it would take an annual salary of about $81,900 to pry them from their current job, up from about $76,600 a year earlier.

In that context, experienced workers with less than a bachelor’s degree seem like a bargain. On average, they said they would leave their job for about $47,300, virtually unchanged from a year earlier.

But how are employers luring these workers, if not with cash?

It’s not benefits. The share of less-educated workers who say they’re satisfied with their benefits has remained essentially unchanged over the past year, at about 63 percent, compared with a record high of 74 percent for their educated peers.

So what’s the culprit?

“There is a significant rise in the proportion of respondents without a college degree who are satisfied with the career progression opportunities at their current jobs,” Kosar told us.

The share of less-educated workers who are satisfied with their opportunities for promotion has soared more than 10 percentage points in the past year. At 51 percent, it’s now five percentage points higher than that of college-educated workers.

“Less-educated workers might be finally moving to firms with higher productivity and with better opportunities for themselves,” Kosar said. In the absence of an immediate salary bump, they are likely counting on raises or more lucrative offers in the future.

“This is an explanation that has been there in the economic literature for some time now,” Kosar said. “Because our survey tracks labor market dynamics in real time, we were able to see empirically what we had in the theory.”

The underemployment and skills mismatches that defined the recovery may be sorting themselves out. Workers may finally be finding jobs that match their talent and ambition, if not their salary requirements.