The elation over wage increases in private business reported in last month’s job report has been replaced by disappointment. The Bureau of Labor Statistics reported on Jan. 16 that average hourly earnings fell five cents in December, eating up most of the six-cent increase in November. Between 2010 and 2014, the average real wage fell 1.1%, a poor showing after rising 3.4% between 2006 and 2010. What accounts for this performance?

There are basically two ways that the average economywide wage can fall. There might be a shift in employment away from high-paying to lower-paying industries; in other words, the economy is producing more “bad jobs.” The other way is that the overall composition of work might be the same, but wages for the typical job in most sectors have fallen.

Normally, economywide wage changes reflect what happens to the wage of the typical job. But between 2010 and 2014 there were also significant declines in the proportion of the workforce employed in two high-paying industries. Those declines contributed to overall wage declines—and they may have been caused by policy mistakes.

The share of the private workforce employed in the BLS-defined industries “financial activities” and “hospitals” decreased by about 5% between 2010 and 2014. Jobs in these industries pay 29% and 24%, respectively, above the economy mean. Because a smaller share of labor is working those high-wage industries, the typical job in the economy is now lower-paying than in 2010.

Nevertheless, the movement of workers out of these two high-wage sectors has been partially offset by increases in other high-wage industries. For example, mining, which benefited from the transformation in oil and gas extraction technology and which pays average wages comparable to those in finance, grew significantly. But because mining employs only about one-tenth the number of workers as finance, even large increases in mining don’t make up the difference.