For the past three US presidential elections I’ve compared the results of the Iowa Electronic Markets two days before election day.

In 2008 and 2012 I posted what the market predicted and waited to see how it would do. In each of those elections the market predicted accurately within a few percentage points of the actual vote. In 2016 it predicted the percentage vote for the Republican candidate within a couple percentage points but was off for the Democratic candidate thought it rightly predicted her getting the higher percentage. It was wrong about the overall winner in 2016.

Before 2016, the IEM had an excellent track record going back to 2000 when it accurately forecast Gore winning the popular vote and Bush winning the election.

Can the IEM do well in 2020?

Let’s review the past numbers and then see what the IEM says today, two days before election day.

Two days before the 2000 election

Who will win
Al Gore – 27.3%
George Bush – 74.9%

Vote Share Prediction
Al Gore – 49.6%
George Bush – 49.4%

Actual result
Al Gore – 48.4%,
George Bush 47.9% – Winner

Two days before the 2004 election

Who will win
George Bush – 55.2%
John Kerry – 45.3%

Vote Share Prediction
George Bush – 51.7%
John Kerry – 48%

Actual result
George Bush – 50.7% – Winner
John Kerry – 48.3%

Two days before the 2008 election

Who will win
John McCain – 11.2%
Barack Obama – 88.3%

Vote Share Prediction
John McCain – 47%
Barack Obama – 53.5%

Actual Result
John McCain – 45.66%
Barack Obama – 52.92% – Winner

Two days before the 2012 election

Who will win
Mit Romney – 29.1%
Barack Obama – 71.8%

Vote Share Prediction
Mit Romney – 48.0%
Barack Obama – 52.8%

Actual Result
Mit Romney – 47.2%
Barack Obama – 51.1% – Winner

Two days before the 2016 election
Who will win
Donald Trump– 29.3%
Hillary Clinton – 70.5%

Vote Share Prediction
Donald Trump– 45.3%
Hillary Clinton – 57.5%

Actual Result
Donald Trump- 46.1% – Winner
Hillary Clinton- 48.2%

Two days before the 2020 election
Who will win
Donald Trump– 13%
Joe Biden – 89.6%

Vote Share Prediction
Donald Trump – 46.8%
Joe Biden – 53.4%

Actual Result
Donald Trump-
Joe Biden-