Be careful trading on exit polls
We're going to be into some of the most-dangerous waters of the election day. It's an information blackhole that's often filled with misinformation, conjecture and misleading data.
One culprit is exit polls. Anyone who survived the Brexit vote will remember all kinds of rumors about polls in both directions. The most-prominent rumor was that a big one showed the vote was for staying in the EU. Later there were all kinds of 'insider trading' accusations about exit polls that showed the opposite.
Nate Silver highlights a particular skew this year. Mail-in voting was done by far more Democrats so they will be under-represented in data. Moreover, numbers from today show that early-morning voting was dominated by Republicans in a number of swing states while Democrats are showing up later. That could also lead to an oversample.
Silver writes:
I would be very careful with early exit polls. Even more so than usual. If there are big splits in the partisan composition of the electorate over the course of the day, and we're seeing that in FL, AZ and NV, exits conducted early on could be quite misleading.
It was around this time four years ago that US equity futures rallied on exit polls showing a strong Clinton result in Florida.
Election night 2016:
