“There’s an increase of about 1 percent in the non-accelerating inflation rate of unemployment. So it’s around 6 percent rather than 5 percent,” says William Dickens, professor of economics and social policy at Northeastern University and former senior economist for Bill Clinton’s Council of Economic Advisers.

This “non-accelerating rate” is known by economists as the NAIRU. It’s a relatively obscure bit of economic jargon, but some economists see it as one measure of the natural unemployment rate. The idea is that below a particular unemployment rate, inflation starts to speed up. So by Dickens’ reckoning, rising prices could become a worry as unemployment edges toward 6 percent.

Why?