Half the median
From the Herald, under the headline “First-home buyers nab new home subsidies”
The AMP 360 First Home Buyer Affordability Report, published yesterday, shows housing remains “affordable” in all regions except Auckland and Queenstown.
The index tracked the lower-quartile (halfway between zero and the median) selling prices of houses and the median after-tax income of typical first-home buyers (a working couple both aged 25 to 29).
The lower quartile is not “halfway between zero and the median”. The lower quartile is the price that 25% of sales are below and 75% are above.
What’s more, the interpretation is obviously wrong. If you take the first Google link, at interest.co.nz, there’s a table by region, and it lists the lower quartile price for Auckland metro as $587000 and Auckland City as $681000. The Herald reports the median price often enough that they must know it isn’t over a million dollars.
While I’m complaining: the data table at interest.co.nz is in a state of sin. It’s not actually a data table; it’s a picture of a data table, a GIF image.
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 »