Who counts?
From ABC News (the West Island one, not the US one): Australia’s population hit 25 million, newest resident likely to be young, female and Chinese
There’s a problem with this headline. Well, more than one. First, the story actually says that about 60% of Australia’s population increase is currently from net migration and about 40% from ‘natural increase’, and that 15.8% of immigrants were from China. So, maybe 10% of the population increase is Chinese immigration, and less than 10% are young, female, Chinese immigrants. The newest resident is definitely more likely to be a new baby than a young, female, Chinese immigrant.
More importantly, though, if you want to say something about the 25th millionth Aussie, it’s not net migration and natural increase you want, but gross migration and births. The Australian Bureau of Statistics press release says “one birth every 1 minute and 42 seconds…one person arriving to live in Australia every 1 minute and 1 second”. So, while 60% of the increase in population is immigration, there’s only about a 40% chance that the first person over the 25-million threshold was an immigrant. Which actually gives a similar ratio — just 1.5 percentage points off — but it’s the right calculation.
And while I appreciate “natural increase” is a technical term in demography, I can’t help feeling it’s an unfortunate phrase in communicating statistics to the public.
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 »
Wait, I’m confused… how do you get a 40% chance that the next arrival is an immigrant?
1 birth every 1.7 minutes = 35.3 births/hour;
1 immigrant every 1.017 minutes = 59.0 immigrants/hour
That’s 94.3 new arrivals, and 59 of them are immigrants. Doesn’t that mean there is a 63% chance that the next new arrival is an immigrant?
6 years ago
How? Um. Posting with jetlag and a cold, probably. It’s surprising how little difference net vs gross makes, actually.
6 years ago
From the Home affairs 2016-17 Migration statistics gives the origin of migrants as :
The major source countries in the migration programme were India (21.2 per cent), China
(15.4 per cent) and the United Kingdom (9.3 per cent).
The selection of ‘young chinese female ‘ is even more baffling. Maybe Indian migration has fallen off a cliff but it doesnt seem likely
6 years ago