Editing Gerrymandering (section)

==Changes to achieve competitive elections==
[[File:map22007.gif|thumb|250px|Electoral divisions in the Sydney area in 2007, drawn by the politically independent [[Australian Electoral Commission]]]]
Due to the perceived issues associated with gerrymandering and its effect on competitive elections and democratic accountability, numerous countries have enacted reforms making the practice more difficult or less effective. Countries such as the UK, Australia, Canada, and most of those in Europe have transferred responsibility for defining constituency boundaries to neutral or cross-party bodies. In Spain, they have been constitutionally fixed since 1978.<ref name="ES_Const" /> [[Open list|Open]] [[party-list proportional representation]] makes gerrymandering obsolete by erasing district lines and empowering voters to rank a list of candidates any party puts forth. This method is used in Austria, Brazil, Sweden, and Switzerland.{{citation needed|date=April 2022}}

In the U.S., such reforms are controversial and face particularly strong opposition from groups that benefit from gerrymandering. In a more neutral system, they might lose considerable influence.

=== Redistricting by neutral or cross-party agency ===
The most commonly advocated electoral reform proposal targeted at gerrymandering is to change the redistricting process. Under these proposals, an independent and presumably objective commission is created specifically for redistricting, rather than having the legislature do it.

This is the system used in the UK, where independent [[boundary commissions (United Kingdom)|boundary commissions]] determine the boundaries for [[United Kingdom constituencies|constituencies]] in the [[British House of Commons|House of Commons]] and the [[Devolution in the United Kingdom|devolved legislatures]], subject to ratification by the body in question (almost always granted without debate). A similar situation exists in Australia, where the independent [[Australian Electoral Commission]] and its state-based counterparts determine electoral boundaries for federal, state, and local jurisdictions.

To help ensure neutrality, members of a redistricting agency may be appointed from relatively apolitical sources, such as retired judges or longstanding members of the civil service, possibly with requirements for adequate representation among competing political parties. Additionally, members of the board can be denied information that might aid in gerrymandering, such as the demographic makeup or voting patterns of the population.

As a further constraint, [[Consensus decision-making|consensus]] requirements can be imposed to ensure that the resulting district map reflects a wider perception of fairness, such as a requirement for a supermajority approval of the commission for any district proposal, but consensus requirements can lead to deadlock, as occurred in [[Missouri]] following the 2000 census. There, the equally numbered partisan appointees were unable to reach consensus in a reasonable time, so the courts had to determine district lines.

In the U.S. state of [[Iowa]], the nonpartisan Legislative Services Bureau (LSB, akin to the [[U.S. Congressional Research Service]]) determines electoral district boundaries. Aside from satisfying federally mandated contiguity and population equality criteria, the LSB mandates unity of counties and cities. Consideration of political factors such as location of incumbents, previous boundary locations, and political party proportions is specifically forbidden. Since Iowa's counties are chiefly regularly shaped [[polygons]], the LSB process has led to districts that follow county lines.<ref name="7_buck_trust.html" />

In 2005, the U.S. state of [[Ohio]] had a ballot measure to create an independent commission whose first priority was competitive districts, a sort of "reverse gerrymander". A complex mathematical formula was to be used to determine the competitiveness of a district. The measure failed voter approval chiefly due to voter concerns that communities of interest would be broken up.<ref>{{cite web|url=http://www.smartvoter.org/2005/11/08/oh/state/issue/4/|title=Issue 4: Independent Redistricting Process – Ohio State Government|publisher=Smartvoter.org|access-date=5 August 2009}}</ref>

In 2017, Representative [[John Delaney (Maryland politician)|John Delaney]] submitted the [[Open Our Democracy Act of 2017]] to the [[U.S. House of Representatives]] as a means to implement nonpartisan redistricting. It ultimately did not pass.<ref>{{Cite web |last=Delaney |first=John K. |date=2017-07-10 |title=Text - H.R.2981 - 115th Congress (2017-2018): To require all candidates for election for the office of Senator or Member of the House of Representatives to run in an open primary regardless of political party preference or lack thereof, to limit the ensuing general election for such office to the two candidates receiving the greatest number of votes in such open primary, and for other purposes. |url=https://www.congress.gov/bill/115th-congress/house-bill/2981/text |access-date=2025-02-28 |website=www.congress.gov}}</ref>

=== Redistricting by partisan competition ===
Many redistricting reforms seek to remove partisanship to ensure fairness in the redistricting process. The [[I cut, you choose|I-cut-you-choose]] method achieves fairness by putting the two major parties in direct competition. I-cut-you-choose is a [[fair division]] method to divide resources amongst two parties, regardless of which party cuts first.<ref>{{cite arXiv|title=A partisan districting protocol with provably nonpartisan outcomes|last1=Pegden|first1=Wesley|date=24 October 2017 <!-- |publisher=Cornell University --> |class=cs.GT|eprint=1710.08781}}</ref> This method typically relies on assumptions of contiguity of districts, but ignores all other constraints such as keeping communities of interest together.  This method has been applied to nominal redistricting problems,<ref>{{cite web|url=https://slate.com/news-and-politics/2018/02/how-the-i-cut-you-choose-method-of-redistricting-could-fix-a-broken-system.html|title=A new method of redistricting could solve gerrymandering|last1=Riedel|first1=Will|date=27 February 2018|publisher=Slate.com|access-date=12 December 2020}}</ref> but it generally has less public interest than other types of redistricting reforms. The I-cut-you-choose concept was popularized by the board game ''Berrymandering''. Problems with this method arise when minor parties are shut out of the process, which will reinforce the [[two-party system]]. Additionally, while this method is provably fair to the two parties creating the districts, it is not necessarily fair to the communities they represent.

===Transparency regulations===
When a single political party controls both legislative houses of a state during redistricting, both Democrats and Republicans have displayed a marked propensity for couching the process in secrecy; in May 2010, for example, the [[Republican National Committee]] held a redistricting training session in Ohio where the theme was "Keep it Secret, Keep it Safe".<ref>{{cite web|url=http://www.dispatch.com/content/stories/local/2011/12/13/study-of-gop-maps-points-to-politics.html|title=Study of GOP Maps Points to Politics|last1=Siegel|first1=Jim|date=13 December 2011|publisher=Dispatch.com|access-date=5 March 2013|archive-date=16 March 2014|archive-url=https://web.archive.org/web/20140316033845/http://www.dispatch.com/content/stories/local/2011/12/13/study-of-gop-maps-points-to-politics.html}}</ref> A 2012 investigation by The [[Center for Public Integrity]] reviewed every state's redistricting processes for both transparency and potential for public input, and ultimately assigned 24 states grades of either D or F.<ref>{{cite news|url=http://openchannel.nbcnews.com/_news/2012/11/01/14839356-behind-closed-doors-gop-and-dems-alike-cloaked-redistricting-in-secrecy|title=Behind Closed Doors: GOP and Dems Alike Cloaked Redistricting in Secrecy|last=Kusnetz|first=Nicholas|date=1 November 2012|work=NBC News}}</ref>

In response to these types of problems, redistricting transparency legislation has been introduced to [[US Congress]] a number of times in recent years, including the Redistricting Transparency Acts of 2010, 2011, and 2013.<ref>{{cite web|url=http://www.govtrack.us/congress/bills/111/hr4918|title=Redistricting Transparency Act of 2010 (2010; 111th Congress H.R. 4918) – GovTrack.us|work=GovTrack.us|access-date=16 April 2013|archive-date=3 April 2013|archive-url=https://web.archive.org/web/20130403102430/http://www.govtrack.us/congress/bills/111/hr4918}}</ref><ref>{{cite web|url=http://www.govtrack.us/congress/bills/112/hr419|title=Redistricting Transparency Act of 2011 (2011; 112th Congress H.R. 419) – GovTrack.us|work=GovTrack.us|access-date=16 April 2013|archive-date=29 September 2015|archive-url=https://web.archive.org/web/20150929080910/https://www.govtrack.us/congress/bills/112/hr419}}</ref><ref>{{cite web|url=http://www.govtrack.us/congress/bills/113/hr337|title=Redistricting Transparency Act of 2013 (2013; 113th Congress H.R. 337) – GovTrack.us|work=GovTrack.us|access-date=16 April 2013|archive-date=16 October 2013|archive-url=https://web.archive.org/web/20131016064415/http://www.govtrack.us/congress/bills/113/hr337}}</ref> Such policy proposals aim to increase the transparency and responsiveness of the redistricting systems in the US. The merit of increasing transparency in redistricting processes is based largely on the premise that lawmakers would be less inclined to draw gerrymandered districts if they were forced to defend such districts in a public forum.

===Changing the voting system===
As gerrymandering relies on the wasted-vote effect, the use of a different voting system with fewer wasted votes can help reduce gerrymandering. In particular, the use of [[multimember district]]s alongside voting systems establishing [[proportional representation]] such as [[party-list proportional representation]] or [[single transferable voting]] can reduce wasted votes and gerrymandering. Semiproportional voting systems such as [[single nontransferable vote]] or [[cumulative voting]] are relatively simple and similar to ''[[first past the post]]'' and can also reduce the proportion of wasted votes and thus potential gerrymandering. Electoral reformers have advocated all three as replacement systems.<ref>See, e.g., Richard L. Engstrom, The Single Transferable Vote: An Alternative Remedy for Minority Vote Dilution, 27 U.S.F.L.Rev. 781, 806 (1993) (arguing that the Single Transferable Voting systems maintain minority electoral opportunities); Steven J. Mulroy, Alternative Ways Out: A Remedial Road Map for the Use of Alternative Electoral Systems as Voting Rights Act Remedies, 77 N.C.L.Rev. 1867, 1923 (1999) (concluding that ranked-ballot voting systems avoid minority vote dilution); Steven J. Mulroy, The Way Out: A Legal Standard for Imposing Alternative Electoral Systems as Voting Rights Remedies, 33 Harv.C.R.-C.L.L.Rev. 333, 350 (1998) (arguing that preferential voting systems enhance minority representation); and Alexander Athan Yanos, Note, Reconciling the Right to Vote With the Voting Rights Act, 92 Colum.L.Rev. 1810, 1865–66 (1992) (arguing that Single Transferable Voting serves to preserve the minority party's right to representation).</ref>

Electoral systems with various forms of proportional representation are now found in nearly all European countries, resulting in multi-party systems (with many parties represented in the parliaments) with higher voter attendance in the elections,<ref>{{Citation|last1=Pintor|first1=Rafael López|title=Voter Turnout Rates from a Comparative Perspective|url=http://www.idea.int/publications/vt/upload/Voter%20turnout.pdf |archive-url=https://web.archive.org/web/20070216045624/http://www.idea.int/publications/vt/upload/Voter%20turnout.pdf |archive-date=16 February 2007 |url-status=live|access-date=7 March 2014|last2=Gratschew|first2=Maria|last3=Sullivan|first3=Kate}}</ref> fewer wasted votes, and a wider variety of political opinions represented.

Electoral systems with election of just one winner in each district (i.e., "winner-takes-all" electoral systems) and no proportional distribution of extra mandates to smaller parties tend to create two-party systems. This effect, labeled ''[[Duverger's law]]'' by political scientists, was described by [[Maurice Duverger]].<ref>{{Cite book|last=Duverger|first=Maurice|url=http://archive.org/details/politicalparties0000duve|title=Political parties: their organization and activity in the modern state|date=1964|location=London  |publisher= Methuen|page= 217|isbn=978-0-416-68320-2}}</ref>

===Using fixed districts===
Another way to avoid gerrymandering is simply to stop redistricting altogether and use existing political boundaries such as state, county, or provincial lines. While this prevents future gerrymandering, any existing advantage may become deeply ingrained. The [[United States Senate]], for instance, has more competitive elections than the House of Representatives due to the use of existing state borders rather than gerrymandered districts—Senators are elected by their entire state, while Representatives are elected in legislatively drawn districts.

The use of fixed districts creates an additional problem, however, in that fixed districts do not take into account changes in population. Individual voters can come to have very different degrees of influence on the legislative process. This [[malapportionment]] can greatly affect representation after long periods of time or large population movements. In the [[United Kingdom of Great Britain and Ireland|United Kingdom]] during the [[Industrial Revolution]], several constituencies that had been fixed since they gained representation in the [[Parliament of England]] became so small that they could be won with only a handful of voters (''[[rotten borough]]s''). Similarly, in the U.S. the [[Alabama Legislature]] refused to redistrict for more than 60 years, despite major changes in population patterns. By 1960 less than a quarter of the state's population controlled the majority of seats in the legislature.<ref>Dr. Michael McDonald, U.S. Elections Project: Alabama Redistricting Summary [http://elections.gmu.edu/Redistricting/AL.htm Dept. of Public and International Affairs George Mason University]. Retrieved 6 April 2008. {{webarchive|url=https://web.archive.org/web/20080624024455/http://elections.gmu.edu/Redistricting/AL.htm|date=24 June 2008}}</ref> This practice of using fixed districts for state legislatures was effectively banned in the United States after the ''[[Reynolds v. Sims]]'' Supreme Court decision in 1964, establishing a rule of [[one man, one vote]].

===Objective rules to create districts===
Another means to reduce gerrymandering is to create objective, precise criteria with which any district map must comply. Courts in the United States, for instance, have ruled that congressional districts must be contiguous in order to be constitutional.<ref>[[wikisource:Reynolds v. Sims|Reynolds v. Sims]] states that "a state legislative apportionment scheme may properly give representation to various political subdivisions and provide for compact districts of contiguous territory if substantial equality among districts is maintained." See also [[Reynolds v. Sims|the Wikipedia article]].</ref> This, however, is not a particularly effective constraint, as very narrow strips of land with few or no voters in them may be used to connect separate regions for inclusion in one district, as is the case in [[Texas's 35th congressional district]].

Depending on the distribution of voters for a particular party, metrics that maximize compactness can be opposed to metrics that minimize the efficiency gap.  For example, in the United States, voters registered with the Democratic Party tend to be concentrated in cities, potentially resulting in a large number of "wasted" votes if compact districts are drawn around city populations.  Neither of these metrics take into consideration other possible goals,<ref>{{cite web|url=https://fivethirtyeight.com/features/hating-gerrymandering-is-easy-fixing-it-is-harder/|title=Hating Gerrymandering Is Easy. Fixing It Is Harder.|last=Wasserman|first=David|date=25 January 2018|website=[[FiveThirtyEight]]}}</ref> such as proportional representation based on other demographic characteristics (such as race, ethnicity, gender, or income), maximizing competitiveness of elections (the greatest number of districts where party affiliation is 50/50), avoiding splits of existing government units (like cities and counties), and ensuring representation of major interest groups (like farmers or voters in a specific transportation corridor), though any of these could be incorporated into a more complicated metric.

====Minimum district to convex polygon ratio====
{{More citations needed section|date=February 2022}}
[[File:Polygons of Georgia Districts 8 and 10.png|thumb|upright=1.3|Smallest possible convex polygons drawn around the [[Georgia's 8th congressional district|8th]] (left) and [[Georgia's 10th congressional district|10th]] congressional districts in Georgia, 2012. To avoid penalizing large areas, the measure is the ratio of the area of the district to the area of the polygon. District 8 will get a lower score than District 10.]]
One method is to define a minimum district to [[convex polygon]] ratio.{{Definition needed|date=July 2016}} To use this method, every proposed district is circumscribed by the smallest possible convex polygon (its [[convex hull]]; think of stretching a rubberband around the outline of the district). Then, the area of the district is divided{{explain|date=December 2015}} by the area of the polygon; or, if at the edge of the state, by the portion of the area of the polygon within state boundaries.

The advantages of this method are that it allows a certain amount of human intervention to take place (thus solving the Colorado problem of [[#Shortest splitline algorithm|splitline districting]]); it allows the borders of the district to follow existing jagged subdivisions, such as neighborhoods or voting districts (something isoperimetric rules would discourage); and it allows concave coastline districts, such as the Florida gulf coast area. It would mostly eliminate bent districts, but still permit long, straight ones. However, since human intervention is still allowed, the gerrymandering issues of packing and cracking would still occur, just to a lesser extent.

====Shortest splitline algorithm====
The [[Center for Range Voting]] has proposed<ref>{{cite web|url=http://www.RangeVoting.org/GerryExamples.html|title=Gerrymandering and a cure—shortest splitline algorithm|publisher=RangeVoting.org|access-date=5 August 2009}}</ref> a way to draw districts by a simple [[algorithm]].<ref>{{Cite web|url=https://www.rangevoting.org/|title=RangeVoting.org – Center for Range Voting – front page|website=www.rangevoting.org}}</ref> The algorithm uses only the shape of the state, the number {{var|N}} of districts wanted, and the population distribution as inputs. The algorithm (slightly simplified) is:

# Start with the boundary outline of the state.
# Let {{var|N}}=A+B where {{var|N}} is the number of districts to create, and A and B are two whole numbers, either equal (if {{var|N}} is even) or differing by exactly one (if {{var|N}} is odd). For example, if {{var|N}} is 10, each of {{var|A}} and {{var|B}} would be 5. If {{var|N}} is 7, {{var|A}} would be 4 and {{var|B}} would be 3.
# Among all possible straight lines that split the state into two parts with the population ratio A:B, choose the ''shortest''. If there are two or more such shortest lines, choose the one that is most north–south in direction; if there is still more than one possibility, choose the westernmost.
# We now have two hemi-states, each to contain a specified number (namely {{var|A}} and {{var|B}}) of districts. Handle them recursively via the same splitting procedure.
# Any human residence that is split in two or more parts by the resulting lines is considered to be a part of the most north-eastern of the resulting districts; if this does not decide it, then of the most northern.

This district-drawing algorithm has the advantages of simplicity, ultra-low cost, a single possible result (thus no possibility of human interference), lack of intentional bias, and it produces simple boundaries that do not meander needlessly. It has the disadvantage of ignoring geographic features such as rivers, cliffs, and highways and cultural features such as tribal boundaries. This landscape oversight causes it to produce districts different from those a human would produce. Ignoring geographic features can induce very simple boundaries.

While most districts produced by the method will be fairly compact and either roughly rectangular or triangular, some of the resulting districts can still be long and narrow strips (or triangles) of land.

Like most automatic redistricting rules, the shortest splitline algorithm will fail to create majority-minority districts, for both ethnic and political minorities, if the minority populations are not very compact. This might reduce minority representation.

Another criticism of the system is that splitline districts sometimes divide and diffuse the voters in a large metropolitan area. This condition is most likely to occur when one of the first splitlines cuts through the metropolitan area. It is often considered a drawback of the system because residents of the same agglomeration are assumed to be a community of common interest. This is most evident in the splitline allocation of [[Colorado]].<ref>{{Cite web | url = http://www.rangevoting.org/SSHR/co_final.png| title = Untitled | website = rangevoting.org| access-date = 30 June 2021}}</ref>
However, in cases when the splitline divides a large metropolitan area, it is usually because that large area has enough population for multiple districts. In cases which the large area only has the population for one district, then the splitline usually results in the urban area being in one district with the other district being rural.

As of July 2007, shortest-splitline redistricting pictures, based on the results of the 2000 census, are available for all 50 states.<ref>{{cite web|url=http://www.RangeVoting.org/SplitLR.html|title=Splitline districtings of all 50 states + DC + PR|publisher=RangeVoting.org|access-date=5 August 2009}}</ref>

====Minimum isoperimetric quotient====
{{See also|Compactness measure of a shape|Polsby–Popper test}}
It is possible to define a specific minimum [[isoperimetric quotient]],<ref name="siam.org">{{cite journal |last1=Case |first1=James |title=Flagrant Gerrymandering: Help from the Isoperimetric Theorem? |journal=SIAM News |date=November 2007 |volume=40 |issue=9 |url=https://archive.siam.org/news/news.php?id=1237 }}</ref> proportional to the ratio between the area and the square of the perimeter of any given congressional voting district. Although technologies presently exist to define districts in this manner, there are no rules in place mandating their use, and no national movement to implement such a policy. One problem with the simplest version of this rule is that it would prevent incorporation of jagged natural boundaries, such as rivers or mountains; when such boundaries are required, such as at the edge of a state, certain districts may not be able to meet the required minima. One way of avoiding this problem is to allow districts which share a border with a state border to replace that border with a polygon or semi-circle enclosing the state boundary as a kind of virtual boundary definition, but using the actual perimeter of the district whenever this occurs inside the state boundaries. Enforcing a minimum isoperimetric quotient would encourage districts with a high ratio between area and perimeter.<ref name="siam.org" />

====Efficiency gap calculation====
{{Main|Efficiency gap}}
The efficiency gap is a simply-calculable measure that can show the effects of gerrymandering.<ref name="TheNewRepublic">{{cite magazine|url=https://newrepublic.com/article/118534/gerrymandering-efficiency-gap-better-way-measure-gerrymandering|title=Here's How We Can End Gerrymandering Once and for All|magazine=The New Republic|author=Nicholas Stephanopoulas|date=3 July 2014|access-date=8 May 2018}}</ref> It measures wasted votes for each party: the sum of votes cast in losing districts (losses due to cracking) and excess votes cast in winning districts (losses due to packing).  The difference in these wasted votes are divided by total votes cast, and the resulting percentage is the efficiency gap.

In 2017, Boris Alexeev and Dustin Mixon proved that "sometimes, a small efficiency gap is only possible with bizarrely shaped districts". This means that it is mathematically impossible to always devise boundaries which would simultaneously meet certain Polsby–Popper and efficiency gap targets,<ref>{{cite journal|title=An Impossibility Theorem for Gerrymandering|journal=[[American Mathematical Monthly]]|volume=125|issue=10|year=2018|last1=Alexeev|first1=Boris|last2=Mixon|first2=Dustin G.|pages=878–884|doi=10.1080/00029890.2018.1517571|arxiv=1710.04193|s2cid=54570818}}</ref><ref>{{cite web|url=https://news.osu.edu/you-cant-tell-a-gerrymandered-district-by-its-shape/|title=You can't tell a gerrymandered district by its shape|date=25 October 2017|work=news.osu.edu|publisher=[[Ohio State University]]|access-date=16 September 2020}}</ref><ref>{{cite web|url=https://www.quantamagazine.org/when-math-gets-impossibly-hard-20200914/|title=When Math Gets Impossibly Hard|last=Richeson|first=David S.|date=14 September 2020|work=[[Quanta Magazine]]|access-date=16 September 2020}}</ref>

Given such theoretical difficulties, a robust, however sub-optimal, anti-gerrymandering rule may be as simple as identifying all maps satisfying a rough efficiency measure, like expected outcome matching voter affiliation proportions, then choosing the one most compact.