Monday, July 20, 2009

"Why Is the Background so Ugly?" and Other Questions

You may wonder:

- Why the background is so ugly: Its color reflects the latest projection! The background is pure blue if I project a Conservative majority, pure red if I project a Liberal one, etc. It is white if the top two parties are tied, and its intensity reflects how close the leading party is to a majority. A bit of an eyesore, but dorky-fun and informative!

- Why arithmetic rather than geometric swing: First and foremost, it's a matter of personal preference, given that neither method is obviously preferable to the other. I haven't done an in depth analysis of what method is better, but intuitively, winning 32-30 doesn't feel 1.5 times safer than winning 47-45. In fact, the former result suggests a three-way race or the presence of many small parties, neither of which usually makes the incumbent safer in the following election. For what it's worth, the Paulitics blog made both an arithmetic and a geometric projection in 2008, and the total absolute error of the arithmetic method was lower by 2.

- Why the use of the Liberal logo is inconsistent: It officially changed after the 2008 election! So I use the old logo in the left column to show the 2008 results, but the new one for my current projections. I plan on doing the same for all parties in the future.

- Why I don't make a popular vote projection: Most of the time, I end up with something that is very close to an arithmetic mean of the most recent polls. As a result, my popular vote estimates aren't very exciting, and I've decided that they're not worth the clutter. I will, however, post the gap between the two top parties according to popular vote (i.e. the Conservatives and the Liberals). Other blogs have various weighting/estimation procedures, and ThreeHundredEight.com lists all recent polls so that you can easily make your own!

- Why the pie charts in the left column do not reflect the seat distributions: They represent the popular vote. Again, in the interest of aesthetics, I did not include the numerical values of the vote shares. But they are embedded in the URL of each pie chart, in decreasing order (which shows up on the charts as clockwise, starting at 3 o'clock).

More questions concerning this blog? Just ask!

Note: Edited on March 3, 2011

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