June 15, 2022
Briefly
- The Herald says House prices: ‘Another bloodbath’ as prices slump again in May for sixth straight month – REINZ figures. Estimates in the story range from 10-15% drop by the end of the year, and maybe 18% peak to trough. In January, the Herald reported that prices had risen 30% in 2021, so even an 18% drop would leave prices about 10% higher than they were at the start of 2021. So even the most optimistic forecast has housing prices pretty much keeping up with inflation over 2021-22.
- Emma Vitz updated her housing price maps for the Spinoff, which you probably saw this time last year
- Len Cook, former Government Statistician of New Zealand and former Chief Statistician of the UK, is Not Happy with the proposed Data and Statistics Bill, replacing the old Statistics Act. As I said on Twitter, you don’t necessarily have to agree with Len, but you do need to pay attention to what he thinks.
- Covid has now killed more White people in the US than Hispanic or Black or Asian, according to a New York Times story. As this Twitter thread points out, that’s because of age differences in the populations of different ethnicities. Mortality rates are lower for White people <45 than Black or Hispanic. The same is true for White people 45-64. And 65-74, and over 75. Because the White population averages older, the total numbers of deaths are higher — but that’s like the way deaths are higher in Australia than New Zealand because the population is larger. Age standardisation is really important if you want to think about reasons for differences between groups
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 »
The problem is that the same houses aren’t being sold at both time points. When the price is high, all the houses for sale are pretty much sold. When the price is low then people get more choosey about whether they sell at the low price and it’s those that are “under-valued” by buyers that don’t get sold. The effective price drop is probably higher then that reported.
3 years ago
Its usually a median or average so individual houses dont come into it. Theres always a range of types of home- apartment or single section dwelling- or location that are their own ‘mini market’ price averages . Plus theres ones that are in poor condition compared to ones newly renovated or even brand new.
3 years ago
Here’s a simplified example. Suppose the same three houses were on the market at the peak and the trough.
Offer at time……….Offer at time
point 1………………point 2
$1M….sold…………$0.9M…sold
$1M….sold…………$0.8M…not sold
$1M….sold…………$0.7M…not sold
The price drop looks like 10% but the effective price drop is 20%.
But then I have skin in the game
https://www.trademe.co.nz/a/property/residential/sale/wellington/wellington/miramar/listing/3590784723
3 years ago
“Age standardisation is really important if you want to think about reasons for differences between groups”
This comes up in survey-based estimates of contraceptive failure rates. For instance, any method favored more by older people will appear to be more effective, since age tends to correlate declining fecundity and increasing maturity and (perhaps) motivation.
I’m sure there are many other subjects areas with similar age standardization issues when dealing with observational data.
3 years ago