Daily, we get a new approval rating on Donald Trump and NONE of them agree.  It seems my Republican friends believe his approval is skyrocketing and my Democrat friends believe it is in the toilet.  Both can’t be right….or can they?

The Battle of the Polling Methods

I did a quick review of the individual polls using data from Real Clear Politics.

The scuffle always seems to track back to Rasmussen Polling.  When a new Rasmussen poll is released, it seems it is covered extensively by Fox News and Drudge.  Why?  Because the polling consistently rates POTUS higher than all the other polls.

Is Rasmussen dishonest?  Or is Rasmussen nailing it and everyone else idiots?

The differences lie NOT with the intentions, but with the methodology.

Rasmussen polls likely voters.  Rasmussen discloses this on their methodology page:

“For political surveys, census bureau data provides a starting point and a series of screening questions are used to determine likely voters. The questions involve voting history, interest in the current campaign, and likely voting intentions.

Rasmussen Reports determines its partisan weighting targets through a dynamic weighting system that takes into account the state’s voting history, national trends, and recent polling in a particular state or geographic area.”

Rassmussen takes into account prior voting history in their methodology – nothing shady and they disclose it.

All other pollsters are polling registered voters or adults.  What is the difference?

Turns out, a lot.

Using RealClear Politics data, I simply grouped the polls by sample type (A=adults, LV=Likely Voters, RV=Registered Voters).  This graph is a simple average of the approval ratings.   (yes, this is a very simplistic way of looking at this problem, but it is illustrative).

As you observe, there is a significant difference between likely voters and all other types.  (You can also observe how flat it POTUS’s rating have been, but that is another post.)

As you can see, different methodologies are leading to consistently different results.

So, which method is correct?  Normally, I would have no issue with Rasmussen’s methodology.  In normal times, voter turnout is remarkably stable from election type to election type; however, these are not normal times.

In special elections leading into today, Democrat candidates are OUTPERFORMING their baseline partisan index by approximately 15%.

This simply means, NON-likely voters are showing up in these elections and are likely to show up for the upcoming midterms – young voters, minorities, and angry people.  Rasmussen is missing these voters in their methods and thus painting a rosier picture than the likely, current reality.

The challenge is partisans on both sides are engaging in misusing polling data to push a narrative, and people are buying it.  People only pay attention to the polls they like, disregard others as ‘bad polling.’  Most people are not informed consumers of polling data and this confusion leads to the further erosion of confidence in polling.

It is a toxic misuse of polling, and it needs to stop.

However, the cynic in me knows it isn’t likely to stop; therefore, we need to become better consumers of polling data.

The next time someone says, “The President is on his way to 50% approval!” you must reply “Among who?”  Because the answer matters….a lot.

PS  For a much deeper dive, Survey Monkey did an excellent write-up/experiment using the Roy Moore Senate race in Alabama and illustrating how different methodologies lead to huge variances in polling results.  Past vote vs. intention: an Alabama Senate race