> A truly efficient gerrymander spreads a winning party’s votes so evenly over districts that very few votes are wasted. A review of four decades of state redistricting plans concluded that any party with an efficiency gap of 7 percent or more was likely to keep its majority during the 10 years before new districts were drawn.
In Wisconsin, experts testified, Republicans scored an efficiency gap rating of 11.69 percent to 13 percent in the first election after the maps were redrawn in 2011.