US one or two jobs reports away from full shift in Fed policy: Economist

The United States is about one labor market report away from a full change in Federal Reserve policy, Barclays' chief U.S. economist, Michael Gapen, said Tuesday.

That's because he believes labor market data are the most important signal about expansion and contraction in the U.S.

"You don't make too much about any one report but the trend is awfully weak," Gapen said in an interview with CNBC's "Closing Bell."

"One or two more reports is going to signal something more pernicious and may very well entail a complete turn in the bias."

He believes there is "maybe" a 30 percent chance of a recession over the next four quarters.

Job creation tumbled in May, with the economy adding just 38,000 positions. The Federal Reserve opted not to raise interest rates in June, and the disappointing report also clouded the possibility of a hike in July.

Fed Chair Janet Yellen addressed the recent slowdown in job growth in her testimony Tuesday on Capitol Hill.

"While it is an important report, I would also emphasize that it's important never to overblow the significance of a single report or a small amount of data," she said.

Gapen believes job creation of around 150,000 or better for the next several months will be enough for the central bank to say the labor markets remain satisfactory. If that occurs, the U.K. votes to stay in the European Union and financial markets stabilize, he thinks the Fed will be in for a September hike.

However, if labor market weakness puts the central bank off a September rate increase, "likely this could be it" for the cycle and the Fed will not raise rates again.

—CNBC's Jeff Cox and Stephen Desaulniers contributed to this report