FiveThirtyEightFiveThirtyEight

PUBLISHED Jan. 25, 2018 at 6:00 AM

The Atlas Of Redistricting

By Aaron BycoffeElla KoezeDavid Wasserman and Julia Wolfe

There’s a lot of complaining about gerrymandering, but what should districts look like? We went back to the drawing board and drew a set of alternative congressional maps for the entire country. Each map has a different goal: One is designed to encourage competitive elections, for example, and another to maximize the number of majority-minority districts. See how changes to district boundaries could radically alter the partisan and racial makeup of the U.S. House — without a single voter moving or switching parties. How we did this »

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Partisan goals
Other goals

Show current district boundaries

Gerrymander districts to favor Republicans

Gerrymander districts to favor Democrats

Match partisan breakdown of seats to electorate

Promote highly competitive elections

Maximize number of majority-minority districts

Make district shapes compact (using an algorithm)

Make districts compact while following county borders

← National map

Chance of being represented by either party

100% D
100% R
Usually Democratic districts Highly competitive districts Usually Republican districts
Current
Usually Democratic districtsHighly competitive districtsUsually Republican districts
Current

The partisan breakdown of districts and the expected number of seats controlled by Democrats and Republicans, based on their long-term likelihood of winning each district

The expected number of seats controlled by Democrats and Republicans, based on their long-term likelihood of winning each district

Expected seat split
MapUsually Dem. districtsHighly competitiveUsually Republican Dem.GOP
Democratic gerrymander
Image of the partisan breakdown of the Democratic gerrymander map
Proportionally partisan
Image of the partisan breakdown of the Proportionally partisan map
Majority minority
Image of the partisan breakdown of the Majority minority map
Highly competitive
Image of the partisan breakdown of the Highly competitive map
Compact (borders)
Image of the partisan breakdown of the Compact (borders) map
Compact (algorithmic)
Image of the partisan breakdown of the Compact (algorithmic) map
Current
Image of the partisan breakdown of the Current map
Republican gerrymander
Image of the partisan breakdown of the Republican gerrymander map

How the maps compare on district competitiveness, minority makeup, respect for local borders, compactness and the efficiency gap, an attempt to gauge how politically gerrymandered a set of districts is

Efficiency gap
A measure of “wasted” votes, by the size of the advantage and which party it favors
ProportionalR+1%
CompetitiveD+3%
Compact (algorithmic)R+3%
Compact (borders)R+4%
Majority minorityR+4%
CurrentR+7%
Dem. gerrymanderD+9%
GOP gerrymanderR+18%
Competitive districts
Number of districts in which both parties have at least a 1-in-6 chance of winning
Competitive242
Compact (algorithmic)104
Compact (borders)99
Proportional82
Majority minority82
Current72
Dem. gerrymander27
GOP gerrymander21
Majority-nonwhite districts
Number of districts in which a majority of the voting-age population is nonwhite
Majority minority143
Dem. gerrymander98
Current95
Proportional93
Compact (borders)92
Competitive91
GOP gerrymander90
Compact (algorithmic)89
County splits
Number of times a map divides counties into different congressional districts
Compact (borders)380
Current621
Proportional659
Competitive661
GOP gerrymander734
Majority minority777
Dem. gerrymander892
Compact (algorithmic)1,660
Compactness rank
Rank by the total length of district boundaries, from shortest to longest
Compact (borders)1
Compact (algorithmic)2
Competitive3
Proportional4
GOP gerrymander5
Majority minority6
Dem. gerrymander7
Current8

Breaking down the maps by race

The number of districts by majority racial or ethnic group and the projected number of nonwhite representatives, based on election results since 2006

Majority-nonwhite districts
MapMajority-white districtsAfrican-AmericanHispanic/LatinoAsian/Pacific IslanderCoalitionAllMajority-nonwhite districtsProjected nonwhite House members
Majority minority292374146114394.8
Proportionally partisan34222310409386.2
Current34019301459585.7
Democratic gerrymander33725311419885.4
Republican gerrymander34523320359084.6
Highly competitive34421300409181.2
Compact (borders)34310191629278.3
Compact (algorithmic)3468241568976.2

More from this series

METHODOLOGY

Methodology

We Drew 2,568 Congressional Districts By Hand. Here's How.

PODCAST & VIDEO

Podcast & Video

Gerrymandering 101

ESSAY

Essay

Hating Gerrymandering Is Easy. Why Is Fixing It So Hard?

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