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Showing posts with label trump. Show all posts
Showing posts with label trump. Show all posts

Thursday, November 05, 2020

Prediction Markets were Batshit Insane this Election

. by Runs With Scissors from flickr (CC-NC-ND)

The elections are over. The biggest loser are the prediction markets.

As I'm writing this, Arizona has already been called for Biden. And PredictIt has it as 30% chance of Trump.

Trump has no mathematically possible way of winning. PredictIt has it him at 20%.

I talked shit about 538, and I was absolutely right, but even they in the end had Trump at just 10%. Models I'd consider more reasonable like The Economist's had Trump at 3%. Prediction markets had him at completely batshit insane 40%.

And as votes started coming, when Trump did a tiny bit better than expected (but at no point was anywhere near having any chance of winning), Trump peaked at completely ridiculous 72%! It was known long in advantage that election day vote will be a lot more Republican than mail in vote, and states were clear how much of each kind outstanding there is. Prediction markets completely missed that, and had Trump as a favourite just because Republicans mostly went there in person while Democrats mostly sent their votes by mail, and it was too hard for them to understand.

Everything I said turned out to be right. If polls were right, elections would have been very easy Biden victory, and the "normal polling error" benefiting Biden would turn them into a Reagan style landslide.

But not only that - "normal polling error" towards Trump, would still mean easy Biden victory. Even unusually high polling error - what we had this year - didn't bring Trump particularly close to competitive territory. Everything that possible could go right for Republicans were perfectly for them - and Trump lost anyway, because his chances were nonexistent.

Polls weren't great, but they were fine. They predicted Biden to win by about +8%. By the time counting will end, he'll end up closer to +4 or +5%. We won't know for a while, as California takes forever to count their votes, so popular votes always ends up more Democratic than it seems on election day.

It turns out Trump was indeed closer in tipping point states, so Electoral College gave me a few points, but it never managed to overcome that kind of lead. There's no reason to predict which party will be at an advantage in 2024.

Real markets work because they're dominated by sophisticated institutional investors, whose job it is to figure things out, and whose predictions are tested every day. We hoped that small prediction markets dominated by small scale amateurs tested once every 4 years would be just as good, but it turns out they failed utterly.

I'm definitely disappointed as for a while it seemed that we might get great rationalist tool for very little money. It turns out it takes more than that.

EDIT: It's November 13th now, Trump lost nearly two weeks ago, every state has been called long ago, most betting sites paid out on Biden (including one where I bet), and Trump is still 12% on PredictIt. Some people must really hate their own money.

Wednesday, August 26, 2020

Why 538 election model is wrong and Biden has an easy win ahead

#TrumpYourCat by jillccarlson from flickr (CC-BY)

538 releases a model predicting what they think is going to happen every elections, and this time they released a crazy one, where "Biden is only slightly favored to win the election", and Trump has insanely high 30% chance of  second term.

This is in stark contrast to everyone else's predictions. For example The Economist gives Trump just 9% chance of winning, and this is a much more sensible number.

In this post I'll explain why 538 believes elections are quite close, and why it's completely wrong.

It's not a terribly sophisticated analysis, but it's too long for a tweet, so I thought I'd put it here.

If you're interested, I wrote "A Guide to 2020 Elections for non-Americans" a while back, and I dislike both Trump and Biden very much.

Why 538 model believes what it does

Their model is very sophisticated, but its basic assumptions leading to their crazy conclusions are fairly straighforward:

  • Biden is far ahead in polls, however:
  • there's still a lot of time until elections
  • things are likely to change until then
  • especially since pandemic year is full of events
  • Electoral College benefits Trump, so he will likely win even if he losses popular vote narrowly
  • the economy went to hell earlier this year, but they think it will improve, and that will somehow benefit Trump

Why 538 is completely wrong - not much time

The only thing they got right is that Biden is indeed far ahead in the polls. They're wrong about everything else.

The elections are a lot closer than they think. In normal times, most people vote on Election Day. This time due to the pandemic a lot more people will vote by mail early, and mail voting opens about a month before Election Day, depending on the state. So for a lot of voters, time until elections is only half of what they think. And people might be voting even earlier as there's a lot of talk about Post Office having trouble processing votes in time.

Even if Biden says the dumbest thing he ever said one week until elections, or Trump single-handedly invents coronavirus vaccine, enough votes will be cast by then that it probably won't matter.

Why 538 is completely wrong - pandemic prevents most campaigning

People don't change political beliefs based on clocks ticking, they do based on events and campaigning. This time due to pandemic there's going to be a lot less campaiging, and people's attention will be largely on other issues.

It's not even certain if the usual debates will happen or not. And even if they do, only the first of the three is supposed to happen before mail voting starts.

Why 538 is completely wrong - people already made up their mind

If you compare Trump's approval ratings with all past presidents, Trump's are the least volatile.

People love Trump, or hate Trump, and there's a lot fewer people in between that could be convinced by the campaigns. So no matter how good Trump's campaign is, it will likely not matter. And likewise, while Biden will almost certainly win, he's also very unlikely to win by 1984 style landslide.

Why 538 is completely wrong - Electoral College advantage can go either way

In 2000 and 2016 elections, Democrats won the popular vote, but Republicans won the presidency. While this might give an impression that Electoral College system inherently benefits Republicans (the way Senate arguably does), if you look back both parties benefited from the system about equally often.

Right now it might look like 2020 map will be similar to 2016 map, and seems to benefit Trump. This thinking is completely mistaken.

If very little changes, Trump will lose terribly, and while he might indeed lose Electoral College by less than popular vote, it will be completely inconsequential.

For elections to be even competitive, fairly big changes must happen. But while it's possible, there's no reason to expect that they'll uniformly apply to all states (in proportion to their "swinginess").

For example if Biden says something that will offend a million Californians and makes them stay at home or vote third party, this will significantly reduce his popular vote share, but it won't matter for Electoral College one bit, since California will go Democratic regardless.

Trump needs not only a really big swing - he needs a swing that's either eerily uniform, or happen in just the right states.

In reality, if a major swing happens, it throws all assumptions about Electoral College advantage out of the window. Even if much bigger swing than could be reasonably expected happens, and Trump somehow manages to reach vote share similar to what he got in 2016 (losing popular vote by 2%), it's actually still quite unlikely that this swing will leave his Electoral College advantage intact, and get him another victory.

Why 538 is completely wrong - the economy will not favor Trump

A popular way to predict elections is by looking at "economic fundamentals". The thinking goes that whenever economy is doing poorly, people blame whoever is in charge for it, and vote for someone else. This is generally true, and after every major economic crisis like 1929 or 2008, governments all across the world got a lot less popular, regardless of which part of the political spectrum they were on, and how much or how little they had to do with causes of the crisis. There's no reason to expect 2020 to be any different.

538 really hates fundamentals models, and for a good reason. While bad "economy" affects people's voting preferences, there's no obvious way to pick a single number for what is the "economy". You can use unemployment, or GDP, or disposable income, or stock market, or so many other indicators, of combinations of indicators. So in year were economy is doing so-so, you can't really use those models to predict much.

Instead of stopping there, 538 somehow decided to ask experts where the economy will go just before elections, and since most expect some recovery from the worst of the lockdowns, they count this as benefiting Trump. While there's a room for reasonable disagreement how to model this, there's no way in hell 2020 economy could possibly benefit Trump, people's memories are longer than a few weeks, and US is still and will likely be in state of mass unemployment.

Are 2020 Elections a foregone conclusion?

Democrats are overwhelmingly likely to win the House - they'll win the popular vote, and there's not even a possibility of Electoral College stopping them. Republican House is about as likely as Nicola Sturgeon becoming the next Prime Minister.

Biden is extremely likely to win presidency - things would need to go really damn well for Trump.

Senate is another matter. Only 1/3 of it is reelected each time, and Republicans do have a meaningful structural advantage there, so it seems fairly close to even who's going to win. And it probably matters more than anything else this year.

If Democrats control the Senate, they'll be able to abolish filibuster, pass pretty much whatever they want, and then possibly also pack Supreme Court with ten new liberal judges that will pronounce all of that Constitutional. They probably won't go that far, but in principle they could.

In Democrats keep the House, and Republicans keep the Senate, then it will most likely be four more years of gridlock regardless of who's the president. The parties hate each other so much, they won't compromise on anything beyond the most routine operations of the government. Biden's policies will be different than Trump's, but presidential policies don't matter as much as people thing, an the next president in 2024 might very well reverse most of them.

And yes, I obviously put money where my mouth is.