Princeton Election Consortium

A first draft of electoral history. Since 2004

A tutorial on partisan gerrymandering

September 7th, 2017, 8:45am by Sam Wang


Here’s a spiffy explainer video on how extreme partisan gerrymandering is committed, and how it can be detected by anyone who’s ever taken a basic statistics class.

Many thanks to the creatives behind this, Kyle McKernan and Danielle Alio of the Princeton University communications office. If you like their work, share it and “like” it!

Tags: Redistricting

7 Comments so far ↓

  • Sophia

    On of the reasons I continue to read PEC is because of this video. You made it simple for a visual learner and I appreciate that. I have shared with a few people already! My thoughts are focused on October 3rd.

  • Colin

    I come from a statistics background. This is great, very informative.

  • LondonYoung

    I love the first minute of this video.
    This is the Utah vs. Nebraska redistricting question.
    (We are all nerds on this site so you know what I mean).
    If people in the city think one way 90 % to 10%, and people in the rural areas think another way, 60% to 40%, then how do we want the law to be?
    It is all very happy if the laws are local.
    But if the rules are to be applied to everyone everywhere and we force the will of the urban super-majority on the rural areas … maybe we have some problems.

    • LondonYoung

      To put it another way, why do we even have districts?

    • Sam Wang

      The difficulty of such a seemingly-reasonable criterion is that it is hard to do uniformly and fairly. In North Carolina, urban voters are packed in Raleigh-Durham-Chapel Hill and in Charlotte I believe, but in other cities they are split among districts to weaken their power. The net result is an overall partisan gerrymander favoring Republicans. Converse splitting can be done to favor Democrats. Considering that cities do not obligingly arrange themselves to be of exact size (state population)/(number of districts), value judgments are inevitable.

    • Andrew

      “To put it another way, why do we even have districts?”

      Because that is the traditional form of governance in Anglo derived democracies. UK, Canada, Australia, etc. all use the same system.

      It’s worth noting that most Anglo countries these days are electing governments with 40% or so of the total votes because they are multi-party democracies, and that many districts are won with far less than a majority.

      50%+1 is a powerful meme that is literally followed nowhere, as is the idea of proportional representation.

      Why have districts? Well, why have States? It would seem the logical conclusion of the animus against districts and gerrymandering and the electoral college would also be to eliminate the states and all semblance of local political control and move to the French system of the total nationalization of politics where a forced 50%+1 through run-offs wins everything.

      The biggest fallacy behind opposition to gerrymandering is the insulting idea that people cannot change their minds politically, split their votes, or that parties cannot moderate or change their positions to change who and where they appeal to and win.

    • Sam Wang

      “fallacy” – people actually have gotten highly entrenched in their voting habits. There is abundant data supporting this fact, and it is the basis for gerrymandering. It is naive or disingenuous to pretend otherwise.

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