Misrepresentation is used in politics as a measure of how well (or badly) a political body represents its constituents. The simplest form is the difference between the percentage of votes a candidate or party receives, and the total amount of representation they have in parliament e.g. Party A receives 20% of the vote, but only 10 out of 100 seats available in parliament, there is a misrepresentation of 10%. The sum over all candidates/parties is the total misrepresentation.
Total misrepresentation can range from 0% (the parliament exactly matches the popular vote) to 200% (the result is entirely in favour of a party who received zero votes), with 100% being the result you’d expect from assigning seats at random.
In the recent election in Australia, the total misrepresentation for the House of Representatives (which forms the government) was 46.5%; that is to say the total disparity between seats won in parliament and the popular vote is extremely significant. The largest misrepresentation comes from the Coalition (Australia’s conservative party), who won 15.2% more seats than they would have if the votes were proportional. The only other significant winner from this system was the Labor party (ostensibly left, but is doing its best to pursue the Coalition rightwards), with a misrepresentation of 11% in their favour.
Nothing more clearly demonstrates how rigged this system is in favour of the duopoly than the only other party with a large misrepresentation: The Greens. With 9.2% misrepresentation against them, instead of receiving 9.2% of seats (14), they received 0.7% (1).
A misrepresentation of 46.5% indicates that our electoral system is deeply flawed, even if we accept its populist nature. Deep changes need to be made, but there’s no political will to make them, as the winners of this system have no interest of losing their control of the political apparatus, and no one funding them wants to risk competition from grassroots movements.