Tag: elections

My 2020 Model

First up I want to be super clear this is NOT A FORECAST or a prediction of what happens on election day. This is a polling aggregation model. Think of it as a fancy Real Clear Politics average except that this model comes up with good estimates of uncertainty and is a little better at predicting the final outcome. This model only predicts well the election at the very end of the cycle. At about six weeks before the electio

This model may not be final. I am going to test a few new features on historical polling data. If they work they will be added in to the 2020 model.

I want to explain why I do what I do.

For starters, I was a little bit surprised when the Economist came out with their model. It did some things I wanted to do. I agree with most of how it is structured. But I didn’t want to basically copy them. I wanted something novel.

One interesting thing I have discovered in my research is that FiveThirtyEight’s model is not that much better at predicting election outcomes (51% for Trump, 49% for Clinton) than basic polling averages where you average the last few polls. My models from my undergraduate research were better than a polling average but not as good as FiveThirtyEight. I wanted to how accurate could a Bayesian election model be that could be run on a standard laptop in a couple of minutes.

Data Inclusion Criteria

I am using the Economist’s I assume that the results in one poll don’t affect the results in another poll. One type of election polls are tracking polls where they interview the same people multiple times. Tracking polls depend on the previous poll results so I exclude them.

The Nuance of Polling

I’m an election modeler, and my entire dissertation is focusing on analyzing public opinion polling data in one form or another. I love polling. Often on this blog or on twitter I’m cautious about a new poll or what an election model can actually tell us. So I thought perhaps I should explain why polling is important even if it may not tell us who is going to be the next President.

I feel there is an imbalance on how polling is viewed. Some approach it as being completely certain and if it is outside the margin of error it is impossible. Others dismiss polling because they can’t understand how one thousand people can tell us what the entire country thinks or that 2016 showed polling was a failure. But neither of these views is accurate.

The truth is polling remains our only rigorous and mathematically grounded tool to estimate public opinion. Elections can be forecast using economic and other data but that is only because the true proportion voting for a candidate is eventually known. But polling can tell us what percentage of individuals approve a certain policy or unravel how an individual’s policy preferences to prevent terrorism are related to their risk assessment of future terrorist attacks (as I’ve done in a recent project). We can understand how and when people’s opinions do and don’t change.

Polling isn’t a magic problem solver. The results from a poll can not be treated as 100% correct. Polling has error. Sometimes that error puts us in positions where all we know is that a race is too close to call or that the country is evenly split in its support for a policy. We have to acknowledge that margin of error won’t solve all our problems and that polling is hard work. It’s not easy to predict who is a likely voter or decide between an expensive phone poll or a larger internet panel or try to determine why someone left a question blank.

It is possible for polling to be very important because it signals to our government what the people want and that sometimes polling doesn’t give us a clear answer. It’s possible for polling to “be wrong” just by random chance. But it is also possible it gives us a clear answer. Often, it gives us something to point to as important for the government to act on in a way that is far more representative than calls to a congressman or your friend’s opinions or social media comments. If followed by leaders, polling could be a pathway for a more direct democracy without forcing every citizen to give opinions on every issue.

This election, it’s important to embrace the nuance in polling. Every poll is unique and needs to be interpreted holistically considering when and how it was conducted. Every poll on the same issue or election should have different results and that’s expected and ok. Polling is usually going to be off by a handful or two of percentage points, but sometimes the message is clear because the support is so strong or weak. But polling can give us answers when nothing else will, and for that, it will always be valuable.