Previously, we saw that today's Senate polls, on average, will have an error of about seven points in the margin, if they are anything like the polls in 2010 and 2012.
What about polling averages? Many, including myself, advise not to worry about individual polls and follow the polling averages instead. How well did they do?
Below you can see the comparison of polling averages computed 50 days from the election of 40 Senate races in 2010 and 2012. In this case and the next graph, I am using the value of the local regression of the poll margins at a given day instead of a simple average.
Instead, on average, they're 5.4 points away from it. That means that polling averages, today, are about 5 points off from the actual result, in one direction or another, if 2014 is similar to 2012 and 2010.
Only three races had polling averages 50 days away from the election that were within one point of the actual margin. Seven races were more than 10 points away.
Fine, so that's 50 days away from the election. What about right before the election?
Find out below the fold.