Measuring “Electability”

Being a data scientist, I tried to put a number on “electability”. Two lessons I took away from 2016 were that (1) the polls of head-to-head matchups between Clinton and Trump were misleading, and (2) Clinton’s favorability ratings were a harbinger of her defeat. So I have been using detailed weekly polls of candidates’ favorability ratings and a simple statistical model to rate and track their ability to win the general election.

Without getting into the grimy details of the model, here is an outline of how I analyze “electability”.

First, the ability to win the general presidential election is the ability to win swing states. The ability to win swing states is the ability to appeal to three distinct groups of voters.

People who voted for Hillary Clinton in 2016. People who voted for Donald Trump in 2016. People who sat on the sidelines in 2016.

These are the three critical, distinct populations that will elect the next president. Here is how I view each of them and combine their opinions to measure electability.

Clinton Voters

There are two key, closely related facts about Clinton voters. First, almost all of them despise Donald Trump. His favorability rating among Clinton voters is usually around just 5%.

Second, likely because of Trump’s unfavorability, the overwhelming majority of them will vote for any Democrat over Trump. Tellingly, exit polls¹ showed that about 13% of 2016 Clinton voters had an unfavorable opinion of her and voted for her, against Trump, anyway. So, while my model takes favorability ratings of this group into account, it also assumes that this group will turn out for any Democratic nominee in very large numbers.

Trump Voters

There is no question that the overwhelming majority of 2016 Trump voters continue to support him now and will vote for him again in 2020. The key fact for Trump voters is that Trump is a historically unpopular president, and this does extend to some of the people who voted for him.

While his supporters are usually portrayed as adoring, devoted, unshakable fans, this picture forgets about the many reluctant voters who carried him to very narrow victories in several swing states. Trump needed the votes of thousands of Democrats to win. About 13% of his voters supported Obama in 2012, and the pre-election surveys and exit polls¹ showed that 15–20% of Trump voters had an unfavorable opinion of him when they voted for him in 2016. This looks to be down to around 10% today, but that still leaves the door open for a Democratic candidate to win the election by swinging a chunk of Trump voters back.

Disaffected Voters

This third group of voters, whom I’m calling “Disaffected Voters”, is a mixed bag of people who rarely vote, who were unsatisfied with the candidates, who voted for third party candidates, who were too young to vote in 2016, and many others. It is hard to make many generalizations about this group or to predict exactly how they will vote (if they will vote) in 2020. I think the best we can do is simply listen to what they are saying in the polls about who they like.

There are four key facts for this group of voters.

First, there are a lot of them out there. The 2016 election had the lowest voter turnout for a presidential election in 20 years, with just 55% of eligible voters participating. At the same time, 5% of voters voted for third party or write-in candidates, the highest amount in 20 years. So this group represents about 48% of all eligible voters.

Second, there are reasons to believe many of them will show up to vote in 2020. The 2018 midterm elections had the highest voter turnout for a midterm since 1966. On top of that, every election will bring in some number of first-time voters. In 2016, supposedly a low-turnout year, 10% of voters had never voted before. So I am predicting that these “Disaffected Voters” will be 10–20% of all voters in 2020.

Third, most of these people still don’t like Trump today. They didn’t like him enough to vote for him in 2016, and polls show that most of them still have an unfavorable opinion of him². This means a Democrat who gains favor with this crowd will not have to convince them to abandon Trump.

Finally, many of these people are very picky. They aren’t inclined to pick between the lesser of two evils. When they didn’t like Clinton or Trump, they just stayed home. Today, when asked if they would vote for the Democratic nominee or Trump, 15–20% of them say, “It depends”², a much higher percentage than any other group.

So, even if this group ends up being only 10–20% of the voters, they may have the greatest potential to carry a candidate across the finish line, especially in the states where the margins were smallest in 2016.

Favorability Scores

For each of the groups described above, I have developed a method for calculating a “favorability score” from the weekly polls administered by The Economist and YouGov². In the surveys, respondents are asked if their opinion of a candidate is “Very Favorable”, “Somewhat Favorable”, “Somewhat Unfavorable”, or “Very Unfavorable”. (“Don’t know” is also an allowed response.) I combine the different responses for a candidate into one score per group.

The scores were scaled to correspond roughly to the percent of people in a group who might vote for a candidate in the general election against Donald Trump, but the scores should not be treated as true predictions.

The overall scores and candidate rankings presented below are based on a weighted average of the three favorability scores calculated with the last six weeks of surveys. The weights were intended to model voters in critical swing states, which have slightly more 2016 Trump voters than Clinton voters as well as a smaller chunk of voters who were on the sidelines in 2016. Scores are not calculated for all Democrats running for the nomination³.

Overall Score = (0.42 × Clinton) + (0.43 × Trump) + (0.15 × Disaffected)