Michigan really does has a gerrymandering problem, according to a non-partisan group’s report.

The Citizens Research Council of Michigan put the state’s Congressional and state legislative districts through three statistical tests. The tests aim to objectively measure whether the state’s district lines reflect a deliberate attempt to skew election results in one party’s favor, or are the natural result of complying with federal Voting Rights Act requirements, geographic considerations, or other non-partisan factors that could influence how district lines are drawn.

The methodologies are complex, and researchers admit they’re imperfect. But the results of all three tests strongly suggest that Michigan is highly-gerrymandered, with current district maps drawn so that Republicans are ensured disproportionate majorities on both the state and federal levels.

In 2014 and 2016, Republicans and Democrats received close to equal numbers of statewide votes in state House races. Yet Republicans hold a 63-47 seat majority. The discrepancy was even worse for state Senate races in 2014, when Republicans took home just slightly more votes but came away with an overwhelming 27-11 majority.

Citizens Research Council president Eric Lupher says the report is an attempt to “think about gerrymandering in a way that goes beyond a simple eye test.”

The result “really does suggest that gerrymandering is affecting how we are electing our officials, and how the people are represented by those officials,” Lupher said.

“I think our report quantifies that yes, in fact, Michigan is gerrymandered. It’s not just sour grapes that one party has won consistently, and the other has been on the outside looking in. The game is being stacked against one of the players in the game, and that’s significant.”

The bluntest weapons used in gerrymandering are known as “packing” and “cracking.” They’re used by the majority party in the state legislature, which is responsible for creating new district maps every ten years, to ensure they get a larger majority of seats than overall vote totals would indicate.

“Packing” draws district lines so that a large number of reliable voters for the minority party are packed into one district, ensuring a candidate from that party wins that district’s races by large margins. However, that party’s overall share of seats is diluted because so many votes were “wasted” running up a huge win.

“Cracking” splits up reliable voters for the majority party into a larger number of districts, in a way that gives that party reliable majorities in those districts by slimmer margins.

One of the statistical tests used to measure gerrymandering, known as the “efficiency gap,” attempts to determine the extent that packing and cracking was used to draw up districts. The CRC report found that Michigan’s efficiency gap scores shifted to favor Republicans in both federal and state races after the 2000 re-districting, and there was “a large increase in the efficiency gap after the 2010s redistricting process as well.”

Lupher notes that Michigan’s efficiency gap scores exceed Wisconsin’s, the state at the heart of a recent court case challenging legislative district maps. The U.S. Supreme Court was asked to consider the efficiency gap as a possible measure for determining whether the extent of gerrymandering in Wisconsin is unconstitutional. The Court declined to take up the case this year, likely leaving the question of a constitutional standard for gerrymandering up to a future court.

Lupher says the CRC wanted to quantify the reality of gerrymandering in Michigan ahead of a possible state ballot proposal.

That proposal, which would take re-districting power away from the state legislature and give it to a citizen commission, is tentatively on the November ballot. Opponents, including Michigan Attorney General Bill Schuette, have petitioned the Michigan Supreme Court to overturn lower court decisions and remove it.