"This is definitely a setback," said T.C. Robillard, a senior research analyst who covers several large staffing firms for Signal Hill Capital.
Jobless claims often bounce around from week to week. They dipped below the 400,000 mark four weeks ago, but then began rising again soon after.
"Broadly speaking, we're taking two steps forward and then one step back," Robillard said. "In my view, that's still progress, but it's certainly slow."
Snowstorms in the Southeast and layoffs of temporary holiday workers could be distorting the January numbers more than usual, some economists say.
Still, the general theme remains the same, Robillard said -- the economy is improving, but at a much slower pace than hoped.
Since the weekly figures can be volatile, economists look at the four-week moving average to smooth out the week-to-week choppiness. That figure rose 15,750 to 428,750 from the previous week, showing a slightly worse job market.
Continuing claims -- which include people filing for the second week of benefits or more -- rose to 3,991,000 in the week ended Jan. 15, an increase of 94,000 from the week before.
Layoffs are slowing but jobs growth still weakJobless claims surge to 457,000
