Ontario County Weighted Voting - Apportionment Plan Based on 2020 Population

CGR was asked to determine the optimal number of weighted votes to apportion to Ontario County’s Supervisors based on the 2020 population numbers, using the Banzhaf Index as a test. This test was required to ensure that residents receive equal and appropriate representation for votes by the Ontario County Board of Supervisors. CGR devised a weighted voting calculation program (coded in Python) that determined Banzhaf Index scores for any given allocation of weighted votes. Utilizing this program, CGR tested approximately a thousand combinations of weighted votes and arrived at two combinations, one for simple majority votes and one for 2/3 majority votes, that reduce the overall discrepancy for all districts between percentage of population represented and Banzhaf Index (proportional power), creating comparable results to the previous (2010 and 2000) voting plans. The plan was presented to Ontario County and adopted for use for the next decade.

Report Date: Mar 2022
Author(s): Kieran Bezila , Tathagata Mukherjee , Paul Bishop
Subject(s): Government Management , Census Data Interpretation
Location: Ontario, New York