WASHINGTON DC, United States — US workers were less productive in the spring for the second quarter in a row, a trend that may not bode well for future hiring.

Productivity dropped 0.3 per cent in the April-June quarter, following a decline of 0.6 per cent in the first three months of the year, the Labour Department said yesterday. It was the first back-to-back decline in productivity since the second half of 2008.

The drop in productivity helped push unit labor costs up 2.2 per cent. That follows a 4.8 per cent rise in labour costs in the first three months of this year, the biggest increase since the last three months of 2008.

Rising labour costs reduce corporate profits. Labour represents the largest expense for most companies. And when workers are less productive and cost more, companies are less likely to add jobs.

The stock market shrugged off the report and prepared to rebound after Monday’s 643-point plunge. Dow Jones futures rose 137 points.

Productivity measures the amount of output per hour worked. Higher productivity is generally a good thing because it can raise standards of living by enabling companies to pay workers more without raising their prices and increasing inflation.

Still, productivity gains can be painful in the short run if they are a result of job cuts. That’s what happened in the recession, when productivity rose sharply as companies laid off millions of workers and figured out how to do more with less. Employees worked harder and companies invested in labour-saving technology and machinery.

A slowdown in productivity growth is bad for the economy if it persists for a long period. It can be good in the short term when unemployment is high, if it means companies are reaching the limits on how much extra output they can get from their existing work forces.

If economic growth increases later this year, less productive companies may have to step up hiring. But the gains are unlikely to be large. Many economists forecast growth of roughly 2.5 per cent in the final six months of the year. That’s barely enough to keep up with population growth.

Economists say a drop in productivity when economic growth has declined is a troubling sign. That likely means companies hired too many workers earlier this year, based on the assumption that growth was picking up. The result: weaker output from a larger workforce.

“If demand remains weak, there’s a danger that businesses may try to boost productivity by cutting jobs,” said Paul Dales, an economist at Capital Economics.

The productivity trends are a sharp reversal from last year, when worker efficiency grew and labor costs fell. Productivity rose 4.1 per cent in 2010, the most since 2002. Labour costs, meanwhile, dropped two per cent, the biggest decline on records dating back to 1948.