Mathematical models and algorithmic metrics evaluate partisan districting and natural geographic bias

The short version

• Researchers and legal scholars are utilizing geometric analysis and metrics like the efficiency gap to identify partisan gerrymandering and measure wasted votes.
• Computer simulations demonstrate that demographic distribution can create natural partisan skews in representation even under nonpartisan, compact districting rules.
• While nationwide net distortions have decreased compared to past cycles, legal disputes over redistricting fairness and minority representation continue to reach the U.S. Supreme Court.

Key facts

• The efficiency gap metric, developed in 2014 by Nicholas Stephanopoulos and Eric McGhee, measures partisan bias by comparing total wasted votes between parties relative to total votes cast.[Scientific American]
• A simulation by researchers Wendy Cho, Yan Liu, and Shaowen Wang generating 250 million potential district maps for Maryland in 2011 showed that the official map favored Democrats more than 99.79 percent of the computer-generated options.[Scientific American]
• Natural geographic concentration of voters in urban areas can lead to asymmetric representation outcomes without intentional redistricting manipulation, as demonstrated in a 2013 study of Florida.[Scientific American]
• Although the U.S. Supreme Court ruled intentional gerrymandering illegal in 1986, it has rarely intervened directly in legislative map boundaries.[Scientific American]
• Alabama's state legislative redistricting prompted litigation before the U.S. Supreme Court over allegations that the map concentrated Black voters into a single district to dilute their electoral power.[Scientific American]

Sources

Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.

• Geometry Reveals the Tricks behind GerrymanderingScientific American metered