... for those of us not used to the Mixed Proportional method, where you get extra "party vote" seats when you, eg, have a party vote share equal to 10 seats, but only win 7 constituencies.

"overhang seats" happen when you are entitled to fewer total seats than the constituency seats you win. You can't take away constituency seats, and the parties that won a larger share than their individual MP's are still entitled to their party list seats, so you end up seating more MP's than the normal total of individual and party list seats.

That happens in New Zealand because of the habit of Maori voters to cast Maori Party constituency votes and Labour Party party votes, leaving MP with fewer total seats than constituency seats won.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.