FairyMander Glossary

A measurement of compactness for each district that ranges from 0 to 1. It is the ratio between the area of a district and the area of the minimum bounding circle around the district. To determine the compactness of the district, the score needs to be closer to 1 for the district to be considered compact. The formula which is represented as \( R = \frac {A_D} {A_{mbc}} \) where \(A_D\) is the area of the district and \(A_{mbc}\) is the area of the district's minimum bounding circle.

Another measurement of compactness. It is the ratio between a district's area and the square of its perimeter. The closer the score is to 1, the more compact the district is. The formula which is represented as \( PP(D) = \frac {4\pi {A_D}} {P(D)^2} \) where \({A_D}\) is the area of the district and \(P\) is the perimeter of the district.

Measurement of competitiveness, where the wasted votes in an election (the votes that did not contribute to the election outcome for a specific party) quantify the degree of partisanship. The metric can be either positive or negative. A negative value indicates a Democratic advantage, while a positive value indicates a Republican advantage in the outcomes. The formula which is represented as \( EG = \frac {W_D - W_R} {T} \) where \(W_D\) is the wasted votes for the Democratic party, \(W_R\) is the wasted votes for the Republican party, and \(T\) is the total number of votes.

District competitiveness measurement that calculates the difference between the average percentages by which each party won in a district. The formula which is represented as \( LMT = {W_A - W_B}\) where \(W_A\) is the average percentage by which party A won in a district and \(W_B\) is the average percentage by which party B won in a district.

Examines how the distribution of district vote-shares affects potential seat outcomes, rather than solely focusing on the nominal seat outcome. Calculates the difference between the median and mean vote-share across all districts for one party The formula which is represented as \(f_{mm}(z) = \text{Median}\{F_k(z)\} - \frac{1}{K} \sum_{k=1}^{K} F_k(z)\). Where \(F_k(z)\) is the vote share of party \(z\) in district \(k\). The mean median difference is calculated for each party in a state.

Measure of minority representation within a district. Each index value indicates how the minority population is distributed across the districts in the state. This metric is measured on a scale from 0 to 1 where values closer to 1 indicate higher segregation of minority populations between districts. The formula which is represented as \( D = \frac{1}{2} \sum_{i=1}^N \left| \frac{a_i}{A} - \frac{b_i}{B} \right| \) where \(N\) equals the number of districts in a state, \({a_i}\) as the population of group \(A\) in a district, \(A\) as the total population of group A, \({b_i}\) as the population of group \(B\) in a district, and \(B\) as the total population of group B.