January 9, 2021

Win Probability vs Expected Margin

I really like how the New York Times had visualizations of not just the win probability but also the expected margin of the recent senate elections. I’m not sure if this is new or if I just haven’t noticed it before, but it’s so much more intuitive.

When I looked at ‘win probability’ dials during the presidential election, even though I knew it was going to be close and even though I knew that win probability is not the same as the expected margin, I couldn’t help feeling like the very high win probability should result in a landslide. I wonder how many other people felt like this and whether that contributed to the anxiety a lot of democrats felt on that first night.

By visualizing both of these side by side, it’s much more obvious that a high expectation of winning doesn’t necessarily mean a wide margin.