The Internet lit up on Monday over the news, reported in New York Magazine, that a team of computer scientists and lawyers had reported to the Clinton campaign that “they’ve found persuasive evidence that results in Wisconsin, Michigan, and Pennsylvania may have been manipulated or hacked.” … Many of my […] Read more »
The polls didn’t fail. We just chose to ignore the math
There’s a lot of talk right now that polling failed. But Trump’s win was hardly an unpredictable “black swan” event. All the evidence was there, if you knew how to read it. In fact, the polls did ok, 2016 was not even a particularly large miss by historical standards. … […] Read more »
Election surprise, and three ways of thinking about probability
Background: Hillary Clinton was given a 65% or 80% or 90% chance of winning the electoral college. She lost. Naive view: The poll-based models and the prediction markets said Clinton would win, and she lost. The models are wrong! CONT. Andrew Gelman, Columbia U. Read more »
When You Hear the Margin of Error Is Plus or Minus 3 Percent, Think 7 Instead
As anyone who follows election polling can tell you, when you survey 1,000 people, the margin of error is plus or minus three percentage points. This roughly means that 95 percent of the time, the survey estimate should be within three percentage points of the true answer. If 54 percent […] Read more »
Poll Aggregation Fight
Last week I got into a little Twitter fight with Nat[e] Silver. I tweeted that I am concerned about the FiveThirtyEight forecast, both how much volatility it has and how predictable the forecast is. … Here is summary of methodological disagreements with Nate Silver (who I find to be a […] Read more »
Rock ‘n Poll: Polls explained with interactive graphics
Politicians as well as journalists take political polls very seriously. Losses and gains of a few percentage points are overly analysed and commented on. This interactive explanation shows you why polling results should be taken with a grain of salt. In a lot of cases decimals will prove to be […] Read more »