Quality score and adgroup keyword volume

Does having a larger number of keywords in an adgroup reduce its Quality Score?

 

I'm not sure that a large number of keywords is by itself a factor. However, a large number of keywords does often indicate that you may have a lot of dead wood dragging down your group. But no, a large number by itself isn't factor: if you had 1,000 keywords all performing excellently, it shouldn't affect your group.

 

then again the 1000 keywords are hardly all quality-filled, so most likely they do reduce it