The 2020 elections are still 18 months away and yet pollsters are out in force, giving us just enough information to break out our crystal balls and make wildly irresponsible predictions. This is the second post in a four-part series looking at the Generic Ballot and its utility as an election predictor. You can read the first post in the series here.
Last post I argued that the Generic Ballot — the polling question that asks respondents if they plan to vote for a Republican or Democrat for Congress — is fairly predictive of election results when the poll is taken right before or on election day. But what about a year and a half out, as we are now from the 2020 election?
Early Generic Ballot polling is tough to track down, but Real Clear Politics has aggregated such polls since the 2004 Bush v. Kerry presidential race. The sample here is very small, only four presidential election cycles, so adjust skepticism accordingly.
In the chart below, I have averaged the results of the first five Generic Ballot polls taken in an election cycle, starting 19 months out from the election1Notice that not every cycle has polling data going back 19 months before the election. 2004 in particular, lacks very early polling data..
In 2008, 2012, and 2016, the early polling was surprisingly accurate, missing real election results by a net average of only 1.7%. The 2004 election polling, though, breaks this trend. The earliest polling projected a Democratic win of 10%, but Republicans won the House Popular Vote by 2.6%, leading to a 12.6% polling miss.
Lacking more historical data, it’s hard to determine if the error in 2004 is an outlier or not. If it is, and early Generic Ballot polling is generally within 1 to 3% of real election results, we could say that the numbers we see now are predictive of what’s to come in 2020. And while control of the House could hinge on this 1-3% polling error, the Generic Ballot polls would still be able to show the world of possible outcomes and which is most likely.
If 2004 is not an outlier, though, and Generic Ballot polling really will miss the mark by double digits about a quarter (or more) of the time, the Generic Ballot this far out cannot show us the world of possible outcomes, or the likelihood of these outcomes. Predicting that the House Popular Vote could be anywhere between a net +6 for Democrats and a net +6 for Republicans does not narrow election outcomes in any helpful way. Because we can’t determine how likely a polling error like 2004 is the Generic Ballot this far out it should not be treated as predictive.
With that caveat, here are all the Generic Ballot polls taken within the past two months from pollsters receiving at least a B- pollster rating by FiveThirtyEight. Note that Morning Consult and Politico have conducted all but one of these polls, which raises the probability that there is a consistent statistical bias in their results, meaning that the data should be treated with even more skepticism.
Clearly, Democrats currently have a consistent advantage in the Generic Ballot, averaging out to 7%. And while, again, this is not predictive 18 months out from election day, it does expose three important things about the current political environment.
1) The wave that swept Democrat’s into power in the House in 2018 has not dissipated. In that election, Democrats carried the House Popular Vote by 8.6%. So, Republicans may have closed this gap by a point or two, but the pro-Democratic sentiment largely remains.
2) Most voters’ Generic Ballot responses are determined by their feelings about Donald Trump. His net approval rating during this two-month period has ranged from about -9% to -13%. Not exactly the same as Generic Ballot polling, but close enough to give the impression that Trump’s approval is a big factor in down ballot decision making (at least in polls).
3) The small gap between Trump approval and the Generic Ballot average is important, though. While most voters who approve of Trump will vote a Republican Representative, and voters who disapprove of Trump will vote Democratic Representative, there is a small number of voters who distinguish between the top of the ticket and down-ballot races, And while this population is small and shrinking, it still exists. When control of the House can hinge on just one seat, any swing can be determinative.
The big question is if Trump will be able to turn his poor approval rating around. He has been stuck around -9 to -13 for most of the last year. If he can pull it closer to even, Republicans have a good chance to win the Generic Ballot and to take the House. If he continues to slum it down near negative double digits, 2020 will almost certainly see continued Democratic control of the House, likely control of the Presidency and possible control of the Senate. That’s the order Democrats are likely to hold or take power: House -> Presidency -> Senate. It’s hard to imagine a world where Democrats win the Presidency and lose the House or where they win the Senate and lose the Presidency and/or House.
Control of the House, though, is not determine by the Generic Ballot or the House Popular Vote. It is decided district by district. Whichever party wins in a majority (or plurality if there are 3rd party winners) of the 435 House seats will hold the House. In the next post we’ll look at how closely the House Popular Vote correlates to seat allocation between the parties and what this means for the 2020 election. The big question we’ll aim to answer: how much do Democrats or Republicans need to win the House Popular Vote to take control of the House?