More Americans need a second job to make ends meet

Underemployment is still at or above pre-recession levels

Stagnant wages suggest 'full employment' is a long way off

How healthy is the US job market, really?

This remains a major question among economists and Federal Reserve officials, many of whom believe a historically low 4.3% jobless rate means the US economy is at, or near, what experts call "full employment."

Just last week, Wall Street cheered the July jobs report showing a robust gain of 209,000 net new jobs, sending stocks to record highs.

Some central bankers, however, argue that low inflation and the absence of wage growth cast doubt on the notion of a fully healed labor market. Two top Fed policymakers this week spoke out against the prospect of additional interest-rate increases.

Komal Sri-Kumar, an economist who runs an independent research shop, says the employment figures released Friday contain "enough information for the yellow light to flash for investors, the Federal Reserve and the Trump administration."

He writes in an opinion piece published on Business Insider that widespread underemployment and stagnant wages mean there has effectively been no economic recovery "for a significant portion of the US labor force."

One trend could be especially ominous: a spike in the number of Americans taking multiple jobs that has effectively reversed a decade-long* decline.

"The plight of low-income workers is underlined by yet another statistic," Sri-Kumar writes.

The Labor Department reports that 7.6 million workers held multiple jobs last month, up 2% from 7.4 million in July 2016. That's back to highs not seen in 20 years. And it should not be mistaken as a sign of healthy entrepreneurship.

"The principal reason workers hold more than one position is that no single job provides a sufficient income," Sri-Kumar adds. "In a robust economic recovery, the number of full-time workers should be rising, and the number of workers employed part-time or holding multiple jobs, should decline."

"The rise in the number of multiple job holders is troubling, and is yet another signal that there is still slack in the labor market," Sri-Kumar concludes. "Are we there yet? No, we are still far from full employment."

As for underemployment, Sri-Kumar points to the U-6 unemployment rate meant to better capture that concept — people working in jobs that are below their qualifications and earning less than they should or need to.

That measure of underemployment stood at 8.6% in July, unchanged from June. It's far below the most recent peak of 17.1%, but, strikingly, it's right around the 8.4% reading in November 2007 — the month before the official start date of the Great Recession.

*This post was updated to correct the last time this many Americans had a second job.