? unverified
The TL;DR version is that there is a range of plausible Democratic margins—between about 8 and 14 points—that come from defensible data choices. The 16-point Democratic margin comes from a mix of assumptions that all push the result in Democrats’ favor and that should probably be discounted. This is still an uncomfortably wide range.
Written of the national vote for the House, from YouGov’s own polling. Read as a stated range of 8 to 14 points for the Democratic margin; settled by the certified national House vote.