IPPSR Launches Partisan Advantage Tracker

May 23, 2022 - Cindy Kyle

Ever wondered whether the electoral districts in your state are fair, or whether they favor one party at the expense of others?

Michigan State University Professor Jon X. Eguia posed that question too and today released a newly built tool to help journalists, policy advocates, candidates, campaigns and citizens ask – and answer – the same question.

Eguia’s newly released Partisan Advantage Tracker, developed with MSU’s Institute for Public Policy and Social Research, is a user-friendly way to measure partisan fairness in elections to the U.S. House of Representatives.

“The goal is to give the public a more scientific way to debate election outcomes,” said Eguia, who spent three months building the calculations that yield four different mathematical measures of fairness.

In the new model, the Partisan Advantage Tracker draws upon results from 2016-2020 elections for U.S. President, U.S. Senate and Governor in each state. Resulting calculations indicate:

  • The number of congressional seats each party should win according to each of four measures of fairness if voters were to vote in a congressional election as they did in those 2016-2020 statewide elections; and
  • The number of congressional seats each party would win, under maps newly adopted as of mid-May in 2022, again if voters were to vote in a congressional election as they did in those 2016-2020 statewide elections

“In theory, our model allows for use of election data from any election,” Eguia said. “We will update the Tracker with new data after each election, and each time a state adopts a new congressional redistricting map.”

The new model builds on previous academic research that allows for political party gains and losses to be computed on the basis of newly drawn voting maps or for fairness to be assessed along a single measure, Eguia said.

The news and policy organization Politico and news and analytical website FiveThirtyEight also publish redistricting trackers that show whether the 2022 maps favor either party compared to the 2012 maps.

“But if the case is that the 2012 maps were unfair, then this comparison to the older maps only tells us how the size of the partisan advantage has changed,” Eguia said. “It doesn’t necessarily tell us whether new maps, drawn after the 2020 U.S. Census, give one or the other party an advantage in seats, relative to the number of seats that should be won under any standard of fair representation”

IPPSR’s Partisan Advantage Tracker takes previous research a step further, Eguia said. It allows for four different notions of fairness to be computed. It is also easily accessible online to virtually anyone interested in following election outcomes, Eguia said.

The new model is a natural outgrowth of an IPPSR report and analysis of Michigan’s new electoral districts drawn by the Michigan Independent Citizens Redistricting Commission. The commission completed its work earlier this year. The U.S. Constitution requires all states to redraw voting districts every 10 years following population counted during the U.S. Census.

As the maps were drawn, questions were raised about their fairness and the advantage they would give to one political party or another, Eguia said.” We have something to contribute to better inform this debate.”

IPPSR Director Dr. Matt Grossmann and Eguia spearheaded the analysis and report supported through a grant from The Joyce Foundation. The analysis represents the work of IPPSR alongside the Center for Local, State and Urban Policy (CLOSUP) in the Ford School of Public Policy at the University of Michigan. CLOSUP is led by Executive Director Tom Ivacko.

“This is the type of powerful, sophisticated work that IPPSR was designed to contribute not only to the academic community, but also to the nation’s policymakers and decisionmakers,” Grossmann said.

“This is truly a team effort integrating research and analytical capacities,” Ivacko said. “We look forward to the Partisan Advantage Tracker’s use in the elections of 2022 and beyond.”

Henry Fleischmann, a University of Michigan Goldwater scholar majoring in mathematics and computer science, also contributed to the research.

Eguia invites journalists, activists, consultants, advocacy organizations, politicians, scholars and campaign managers to test the Partisan Advantage Tracker.

“If they wonder: ‘are electoral maps for the next election fair, or is the playing field tilted to favor one party over another?’ Then we hope they find in our Tracker an informative and easily understandable answer, for each state, and nationwide. Further, for legislators or jurists working to fix unfair electoral maps, we hope the Tracker provides them with another to use in their pursuit of fairer maps.”

“Ultimately, I see the Partisan Advantage Tracker as a tool to inform the public,” he said. “Ideally, I hope it benefits the public.”

IPPSR is a unit of MSU’s College of Social Science. It specializes in policy analysis, leadership development and survey research through the Public Policy Forums, Correlates of State Policy, Michigan Policy Insiders Panel, State of the State Survey, Michigan Political Leadership Program and the Office for Survey Research.