The number of Americans signing up for unemployment compensation rose last week, an exception to the generally improving trend in the U.S. job market.

Thursday’s report from the Labor Department says first-time jobless claims rose 15,000 to a nationwide total of 381,000.

But economists say averaging unemployment claims over a four-week period gives a more accurate picture of the economy. By that measure, jobless claims are at the lowest level in more than three years.

Experts say a decline in layoffs may be a step toward increased hiring.

The U.S. unemployment rate comes from a different study, and that data will be published on January 6th. Economists surveyed by the Bloomberg financial news service say the jobless rate might rise slightly from November’s 8.6 percent. They also predict the data will show that the U.S. economy had a net gain of 150,000 jobs in December.