Princeton Election Consortium

A first draft of electoral history. Since 2004

Meta-Margins for control: House D+1.0% Senate R+4.2% Find key elections near you!

House Outlook: Streams Converge

November 5th, 2018, 2:00pm by Sam Wang


As has been the case for months, Democrats are still favored to win the House. But measured in terms of national popular vote, they are only 2 or 3 percentage points above threshold to do so. That’s pretty close…and all of them touch the threshold for control by either side.

What makes everyone think the House will go Democratic? Let me list three streams of evidence. They all point the same way, but none are definitive. The streams are based on (1) polls, (2) real results from special elections, and (3) district-by-district analysis.

The generic Congressional ballot. PEC’s Meta-Margin is defined purely in terms of generic Congressional ballot polls. By this measure, the House has been between 1.5 and 3 percentage points above threshold for Democratic control (I estimate threshold = a 6% margin in the national popular vote, i.e. polls suggest a popular-vote win of 7.5-9.0%). The blue band on the beta site displays the 90% confidence band on this measure. That band shows a popular-vote range of Democrats by 5-12%. The bottom of that range indicates Republican retention.

Special elections (real elections, no polls). These have predictive value, and suggest that Democrats are 3 percentage points above threshold for a takeover. The pink band displays the 90% uncertainty band, a range of a popular-vote win of 6-12% for Democrats.

Note that this stream of information is based on real elections, not polls. This is a huge advantage. It has the disadvantage that when there’s one special election at a time, national energy can be brought to bear on a single district. Did the outpouring of get-out-the-vote activity these last few weeks match that intensity? We don’t know yet.

Expert evaluations. Larry Sabato and Kyle Kondik have their final picks. They apply their expert judgment, which includes district-level polls, funding, and candidate quality. They end up with 229 Democratic seats – a handful over the 218 needed for a majority. That corresponds to a national popular-vote win of about 9-10% for Democrats. However, note that about 30 were listed until recently as toss-ups, which would suggest an 90%-confidence-band of plus or minus 9 seats.

Despite the near-certainty of a convincing popular-vote win, the question of control is still a little up in the air. The basic reason is gerrymandering, which I estimate gives Republicans about a 3-point bonus.

Voters can address the offense of gerrymandering tomorrow with ballot initiatives in Michigan, Utah, Missouri, and Colorado to establish balanced redistricting processes. Only one, Michigan, currently has a partisan gerrymander. In the others, the initiatives are just good government.

Tags: 2018 Election · House

6 Comments so far ↓

  • Prabhakar Vaidya

    thank god … einstein… ur cite exists

    sick of seeing nate …. he thinks the joint
    p of .5 and .5 is 0.5

  • A Princeton GS Alumnus

    I trust you guys more than other pollsters. That said, I doubt your numbers. Almost all pollsters are left-leaning and lie with fake poll numbers to suppress and discourage Republican turnouts, as they have done for ages. It didn’t work in 2016. It won’t work this time, either. Have you addressed the record early voting numbers by the Republicans? You will need a miracle on Tuesday to counter that. God sent Trump to save this country from being destroyed by the criminal Democrats (and RINOs) who have sold this country out to China and the globalists. Let’s see what the people say tomorrow. Good night.

    • Sam Wang

      The special-election number is not based on polls at all. It is based on real election results.

    • Geoff

      Finally, a response filled with fact based evidence. An excellent, thoroughly convincing takedown of Wang that will no doubt leave him crying. Kudos to you, obviously real Princeton graduate.

    • Sam Wang

      Usually I filter foolish comments like that one, but the obviously false self-report was just too amusing.

  • Marco

    Sam:
    you are more saintly than I am. But hey, I am a criminal… :)

Leave a Comment