Seats-to-votes ratio
The seats-to-votes ratio, also known as the advantage ratio, is a measure of equal representation of voters. The equation for seats-to-votes ratio for a political party i is: a i = s i / v i {\displaystyle \mathrm {a_{i}} =s_{i}/v_{i}} , where v i {\displaystyle \mathrm {v_{i}} } is fraction of votes cast for that party and s i {\displaystyle s_{i}} is fraction of seats won by that party.