In a previous post, I calculated the voting power index for every state and federal election over the last election cycle. But not all of these seats will be contested next year, so I thought it would be interesting to select out just the 2020 elections for a new analysis. As a reminder, the voting power values are calculated using this equation:
This calculation is explained more in the previous post, but the main point is that it allows me to combine both the importance and margin of an election into a single metric. These values can then be aggregated and compared across different states. All the code for this project is available on GitHub here.
So, without further ado, here are the results for 2020:
And here’s a table of the results, note that the table is sorted by the 2020 voting power value.
So although Florida leads in the previous
voting_power calculation, it ranks four spots lower in the
voting_power_2020 numbers. This is because although there were many close elections in Florida over the past cycle, fewer of those seats are up for reelection in 2020.
North Carolina on the other hand has elections at every level of government in 2020. Many of those elections will have close margins, resulting in a higher voting power value. I think this underscores the importance of considering every election in an analysis instead of just thinking about the presidency. An approach like this allows you to make the best use of limited resources by focusing on places where your effort helps more than one campaign. It’s not reflected in this analysis, but North Carolina has additional appeal for Democrats in 2020 because its maps for congress and state legislature will have to be redrawn due to an unconstitutional gerrymander. This gives Democrats an additional incentive to focus on this state.
Note that I also included per capita spending and the D:R ratio of spending in the table above. I find this data useful because it gives me an idea of the marginal benefit of investing in a state. For example, if a place already has really high per capita spending or if your party already outspends your opponent 2:1, it probably doesn’t make sense to spend more resources there. These numbers are courtesy of the Center for Responsive Politics over the 2014-2018 election time period. In the future, I might try to incorporate the per capita spending directly into the index but it adds too much complication for now.
Here’s the breakdown by office for the top ten states:
One thing that concerns me about this analysis is that it may overfit to the results of past elections. Instead, I could use aggregated polling data for each election to predict the future margin, then combine this with the
seat_potential_power to make a live-updating index. Maybe I’ll start doing this once 538 or another polling aggregator starts publishing predictions for the 2020 elections.
 The Center for Responsive Politics, opensecrets.org. https://www.opensecrets.org/overview/statetotals.php
 Where do voters have the most political influence?. https://pstblog.com/2019/03/05/voting-power-comprehensive
 Source code, voting-power-comprehensive https://github.com/psthomas/voting-power-comprehensive