Supplemental - Exploratory Data Analysis


See below for some earlier iterations of static visualizations done in Python matplotlib for exploration and data analysis purpose, with some insights we’ve learned from studying them:

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Efficiency Gap
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Democratic Seats
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Mean Median
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Number of Cuts
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NUmber of Splits
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Democratic Percentage Vote

Insight: efficiency gap is really just share of democratic seats +/- some noise (not a very good metric at all - none of them are!). Insight: Mean median score is uniformly distributed across plans.

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Efficiency Gap-Mean Median

Insight: The above graph shows about the correlation on distribution for efficiency gap and mean-median distribution. The smaller the absolute values of the gap, the larger the range for mean-median distribution, with tail towards left. Also, most observations lies in between reasonable efficiency gaps, with mean-median distribution (double exponential distribution) centered around 0.

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Efficiency Gap-Democratic Seats
The above graph shows the interaction of distribution between efficient gap and the number of seats won by democrat party. The most even distribution (with close to 0 efficiency gap) lies with 6 seats taken by the democrats, and the larger difference on efficiency gap will result in 7 seats taken by the democrats.

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Democratic Seats-Mean Median

The smaller the number of seats taken by democrats, the larger the difference in mean-median distribution (for a number of more than 6 seats). What would be a good interpretation of such correlation? Shows that mean median is not a good indicator of # seats. The mean median left tail is a quite VA-specific thing.

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Efficiency Gap-Vote Percentage

When plotting the distribution of efficiency gaps against the distribution democratic vote shares, it is interesting to see the positive slope between those 2 metrics. Thus, as Democrats increase their vote share, the efficiency gap tends to suggest more of a Democratic advantage.

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Efficiency Gap-Cuts

Contrary to popular belief, this one shows that it is not necessarily true that fewer cuts mean better efficiency gap!

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On average, Virginia is a “naturally” democratic state. The histogram shows the distribution of the ratio (#Dem seats / #Rep seats) across plans. It confirms that that ratio is more than 1 in most cases.