Fair comparisons
When we look at the impact of particular government strategies in Covid, it’s important to compare them to the right thing. The right comparison isn’t, for example, pandemic with lockdowns vs no pandemic — ‘no pandemic’ was never one of the government’s options. The right comparison is pandemic with lockdowns vs pandemic with some other strategy.
Along these lines, Stuff has a really unusual example of a heading that massively understates what’s the in the story. The headline says Covid-19: Pandemic measures saved 2750 lives, caused life expectancy to rise, based on a blog post by Michael Baker and his Otago colleagues. As you find if you read on, the actual number is more like 17,000 or 23,000 (or even higher).
The 2750 is the difference between the number of deaths we’ve seen during the pandemic period and the number we’d expect with no pandemic measures and also no pandemic. The fair comparison for the impact of pandemic measures isn’t this, it’s the comparison to what we’d expect with a pandemic and the sort of pandemic measures used in other countries. According to Prof Baker, we are at minus 2750 excess deaths per 5 million people, the US is at about 20000 excess deaths per 5 million people and the UK at about 13700 excess deaths per 5 million people. The difference: 13700- -2750 or 20000- -2750 is the impact of having our pandemic measures instead of theirs.
There’s room to argue about the details of these numbers. The UK is more densely populated than NZ and was run by Boris Johnson, so you might argue that the UK deaths were always going to be worse . Alternatively, the UK and US have more capacity in their medical systems than NZ, so you might argue that NZ deaths with a similar outbreak would have been worse. What’s important, though, is to compare our choices with other choices New Zealand could have made. No pandemic wasn’t one of those options.
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 »
Theres also a drop in deaths from recent elective surgery due to reduced numbers of operations. It certainly surprised me to hear that roughly 1/3 or so of ICU patients come from the elective surgery stream. Delays do have bad outcomes for some
3 years ago
Shouldn’t we be doing this sort of thing at the end (if it ever comes) of the pandemic? We’re at different stages of the process.
3 years ago
There’s no need to wait until the ‘end’, as long as you realise things will change over time. I mean, if you wait long enough, everyone will die exactly once, but that’s not a more meaningful summary than one at a point in time
3 years ago
I think ‘now’ is also a news hook of 2 years since first covid cases publicised in NZ
3 years ago
I guess the point is “why are we at different stages of the process”. Some of that is policy choices so I don’t think it’s so wrong to compare at the same points in time when we are comparing policy outcomes. But, I guess it would be fairer to compare two countries after they have had their omicron peaks as long as the peaks aren’t too far apart in time – that just brings up other problems.
3 years ago