How low must unemployment go for workers to get a raise?

A couple of decades ago, it was normal for workers to get regular pay increases. After declining mercilessly since the early 1970s, the hourly pay of private-sector production and nonsupervisory workers — nurses, cashiers, manufacturing workers on the shop floor and such — hit bottom in 1995 and rose by more than a tenth in real terms over the following eight years.

Wages improved up and down the scale as the economy hit full employment. The hourly wage of workers at the bottom tenth of the income distribution rose 11 percent from 1995 to 2000, according to the Economic Policy Institute. It rose almost 8 percent for workers in the middle.

Raises are again in the cards. After a long stretch of headlines about stubbornly low wage growth, pay has perked up as the unemployment rate has dipped to levels not seen since the dot-com boom. The median weekly earnings of full-time workers in the middle of the pay ladder ended last year up 4.5 percent from their nadir in the spring of 2014, after accounting for inflation. Target and even Walmart have granted their workers raises.

It is high time: Median weekly earnings are only 3 percent higher in real terms than at the millennium. And yet for all the enthusiasm over the economy’s return to full employment, the pay increases of the halcyon 1990s are probably not coming back anytime soon. For one thing, the economic pie is growing more slowly — held in check by lackluster investment, stunted business dynamism and low productivity growth.