The Gerrymandered States of America

Antimander is an open-source interactive application which is designed to detect gerrymandering within congressional districts. Using Antimander you can explore thousands of alternative congressional district maps to view how different electoral districts can radically alter the electoral results in different states.

Using the Antimander interactive map tool you can explore how Wisconsin's eight different districts can be redrawn to provide different electoral outcomes. In the last U.S. election the votes were fairly evenly split between the Republicans and Democrats (Trump narrowly won the popular vote) however the Republicans won 5 out of the 8 electoral districts. In other words the current electoral map in Wisconsin gives the Republican party an unfair advantage.

Antimander allows you to adjust three different metrics and immediately see how these would effect the electoral outcomes in Wisconsin. The metrics you can adjust are compactness (more complex district boundaries are a good indicator of gerrymandering), competitive elections (close races in each district) and fairness (the number of elected representatives corresponding as closely as possible to the percent of voters for each party).



If you want to know how gerrymandered your state's districts are then you can refer to Planscore. PlanScore has mapped the level of gerrymandering in all 50 states in the USA. PlanScore includes a comprehensive historical dataset of partisan gerrymandering, so you can examine the history of gerrymandering in each state and which political parties the districts have been gerrymandered to support.

The PlanScore choropleth map shows the level of gerrymandering in each state for both the House and State House elections. The darker the red or blue colors on the map then the more skewed the districts are towards the represented political party. If you select a state on the map you can view a more detailed report on the partisan bias in that state and how that compares to the level of gerrymandering in other states.

PlanScore has also developed a scoring service which allows you to test how fair or gerrymandered new district plans are. To use this service you just need to upload a shapefile or GeoJSON file of a district plan. PlanScore will then reveal the levels of the plan’s underlying partisan skew, showing how much the plan has been gerrymandered.

Also See

What's Your Vote Worth - an interactive story map which explores the history of America's voting system, the right to vote and how voter representation is skewed under the present system and map. The story map includes a choropleth view of how much one vote is worth in each state.

The Gerrymandering Project - FiveThirtyEight has had a go at redrawing America's voting districts for themselves. In the Atlas of Redistricting FiveThirtyEight has created a number of new congressional maps, each designed to show how districts can be redrawn to favor different political parties.

How Gerrymandered is your Congressional District? - this 2014 map from the Washington Post colors each congressional district based on its gerrymandered score (determined by the Post's analysis).