Averages and diversity
The NZ Herald has a headline “Little diversity in New Zealand’s average politician“.Of course there’s little diversity in an average — that’s what a one-number summary is for — but the article is mostly about representativeness.
The article says that the typical MP “was a straight European man, from the North Island, aged in his 50s”. If we compare MPs to other people in full-time employment, we see that they are also most likely to be straight, European, male, and from the North Island, though younger than 50.
The interesting question is which groups are under-represented, and why. MPs are substantially older than the rest of the employed population. Women are substantially under-represented. Maori are slightly over-represented relative to their population, which is by the design of the electoral system. Pacific Islanders and Asians are under-represented, by a large enough margin that it’s not entirely due to some migrants only being residents, and so eligible to vote but not to stand for election. And at 95%, straight people are slightly under-represented.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »