{"type":"ScholarlyArticle","title":"Big City vs. the Great Outdoors: Voter Distribution and How It Affects Gerrymandering","authors":[{"name":"Allan Borodin","slug":"allan-borodin","given":"Allan","family":"Borodin","affiliation":"University of Toronto"},{"name":"Omer Lev","slug":"omer-lev","given":"Omer","family":"Lev","affiliation":"Ben-Gurion University"},{"name":"Nisarg Shah","slug":"nisarg-shah","given":"Nisarg","family":"Shah","affiliation":"University of Toronto"},{"name":"Tyrone Strangway","slug":"tyrone-strangway","given":"Tyrone","family":"Strangway","affiliation":"University of Toronto"}],"abstract":"Gerrymandering is the process by which parties manipulate boundaries of electoral districts in order to maximize the number of districts they can win. Demographic trends show an increasingly strong correlation between residence and party affiliation; some party’s supporters congregate in cities, while others stay in more rural areas. We investigate both theoretically and empirically the effect of this trend on a party's ability to gerrymander in a two-party model (\"urban party\" and \"rural party\"). Along the way, we propose a definition of the gerrymandering power of a party, and an algorithmic approach for near-optimal gerrymandering in large instances.\r\n\r\nOur results suggest that beyond a fairly small concentration of urban party's voters, the gerrymandering power of a party depends almost entirely on the level of concentration, and not on the party's share of the population. As partisan separation grows, the gerrymandering power of both parties converge so that each party can gerrymander to get only slightly more than what its voting share warrants, bringing about, ultimately, a more representative outcome. Moreover, there seems to be an asymmetry between the gerrymandering power of the parties, with the rural party being more capable of gerrymandering.","doi":"10.24963/ijcai.2018/14","url":"https://ijcai.org/proceedings/2018/14","pdf":"https://ijcai.org/proceedings/2018/0014.pdf","markdown":"https://ijcai.org/proceedings/2018/14.md","bibtex":"https://ijcai.org/proceedings/2018/bibtex/14","volume":{"slug":"2018","title":"Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2018","url":"https://ijcai.org/proceedings/2018/","year":2018,"location":"Stockholm","dates":"13-19 July 2018","editors":"Jérôme Lang","isbn":"978-0-9992411-2-7","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2018"},"section":"Agent-based and Multi-agent Systems","track":"Main track","number":14,"pages":{"first":98,"last":104},"keywords":["Agent-based and Multi-agent Systems: Voting","Agent-based and Multi-agent Systems: Computational Social Choice"],"videos":[],"references":[{"position":1,"raw":"[Altman, 1997] Micah Altman. 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