Third-quarter gross domestic product released last week showed the euro zone barely growing with No. 2 economy France contracting and No. 1 Germany's pace of growth slowing.
Analysts at Barclays described the euro zone as undergoing "a somewhat disappointing recovery".
The consensus forecast for the flash euro zone composite PMI, incorporating both manufacturing and services, is for a very slight rise to 52.0 from 51.9 a month earlier.
That would indicate expansion and be the highest since the middle of 2011. But it is still below its long-term average.
The U.S. economy is, on the face of it, in better shape. GDP grew at an annual 2.8 percent in the third quarter, albeit boosted by inventories.
But data has not been not uniformly upbeat. Weekly jobless claims and trade numbers last week showed weaker progress than expected.
A Reuters poll suggests that the Philly Fed's business index - one of the first looks at November - will fall quite sharply.
Yellen, meanwhile, has made clear that she sees the economy as below its potential. She intends to keep working at getting it into sustainably strong shape.
Source: Corliss Online Group Financial magazine