WASHINGTON (AP) — Evidence of healthy U.S. job growth would help soothe investor jitters about a possible economic slowdown and that's raised the level of anticipation over this week's government employment reports.

Stock markets have sunk after signs of weaker growth in the United States, Europe and China. The upheaval has renewed doubts about the Federal Reserve's next steps.

But there are pitfalls in putting too much stock in tomorrow's report on January employment. It could be distorted by unseasonably cold winter weather. Revised estimates of job growth last year and the size of the U.S. population might further skew the data.

And a cutoff of extended unemployment benefits in December might have caused an artificial drop in January's unemployment rate.

Payroll processor ADP said yesterday that businesses added 175,000 jobs in January. But ADP's figures cover only businesses and frequently diverge from the government's more comprehensive count.