• Communities of Interest: Communities of interest may include, but shall not be limited to, populations that share cultural or historical characteristics or economic interests. Communities of interest do not include relationships with political parties, incumbents, or political candidates
  • Compactness: There are a variety of definitions of compactness that capture aspects of districts’ appearance and shape. Compactness can be assessed through the use of visual and statistical tests, as well as testimony of community members. The quantitative compactness metrics typically capture how close a legislative district’s boundaries are to its geographic center and how “regular” in shape a district appears to be.
  • Cracking: A form of vote dilution that occurs when district lines divide a geographically compact minority community into two or more districts such that the minority community is not a significant portion of any district. If the minority community is politically cohesive and could elect a preferred candidate if placed in one district but, due to cracking, the minority population is divided into two or more districts where it no longer has any electoral control or influence, the voting strength of the minority population may be diluted. (Also known as Fracturing).
  • Efficiency gap: Partisan gerrymandering is carried out by cracking a party’s supporters among many districts, in which their preferred candidates lose by relatively narrow margins; and/or by packing a party’s backers in a few districts, in which their preferred candidates win by enormous margins. The efficiency gap mathematically captures the packing and cracking that are at the heart of partisan gerrymanders. It measures the extra seats one party wins over and above what would be expected if neither party were advantaged in the translation of votes to seats (i.e., if they had the same number of wasted votes).
  • Gerrymander: The drawing of electoral districts to give one group or party an undue advantage over another group. Drawing majority-minority districts to comply with the Voting Rights Act is not gerrymandering.
  • Packing: A form of vote dilution prohibited under the Voting Rights Act in which a minority group is over-concentrated in one or a smaller number of districts than necessary. For example, packing can occur when the Black population is concentrated into one district where it constitutes 90% of the district, instead of two districts where it could constitute 45% of each district.
  • Partisan Fairness: Neither party should have an advantage in the translation of votes to seats in the legislature, and the party that wins the majority of the votes should also win a majority of the seats.
  • Partisan Gerrymandering: Districting plans that are drawn as a partisan gerrymander distort the relationship between the share of votes that each party receives and the partisan composition of the government in order to systematically advantage one party. This leads citizens from the advantaged party to have more political voice than members of other parties.
  • Reapportionment: Following each decennial Census, the 435 seats in the U.S. House of Representatives are apportioned to each state based on state population.148 The larger the state population, the more congressional representatives the state will be apportioned. This occurs so that a state’s representation in Congress is proportional to its population. Reapportionment is not redistricting, although some states use the terms interchangeably.
  • Redistricting: The process used by governments to redraw electoral district boundaries; redistricting applies to all levels of government where district elections are held— from local school boards, cities and counties to state legislatures and the U.S. House of Representatives. Maps are redrawn every ten years after the Census to create districts with substantially equal populations to, at minimum, account for population shifts.
  • Voting Rights Act Compliance: The federal legislation passed in 1965 to ensure that state and local governments do not pass laws or policies that deny American citizens the equal right to vote based on race. Section 2 of the VRA protects voters from discrimination based on race, color, or membership in a language minority group in all election procedures.