15 August 2020 | New Scientist | 51deaths at home, some 15,000 over the period
we’re looking at – and that's still happening.
As we speak, there’s still a deficit of non-covid
deaths in hospital and an excess in the home.
Again, that just raises more questions. We
don't know the quality of these deaths. Most
people would prefer to die at home; dying in
hospital in this current crisis has not been a
good thing. But maybe some of these people
might have lived longer, had they gone to
hospital. So this just raises more questions,
as we go round and round that data cycle.Coronavirus and age
Let’s look now not just at the death rates, but
the chance of someone in the population
catching covid-19 and then dying (diagram
below left). I think this is almost the most
staggering bit of analysis I've ever done. In
England and Wales, there is a completely
exponentially increasing risk of catching it
and dying from it for the different age groups.
It increases by about 12 to 13 per cent for each
year older you are, and so doubles for every
five to six years. That means that someone
who is 20 years older has got 10 times the risk:
compared to a 25-year-old, a 45-year-old has
ten times the risk, a 65-year-old 100 times, an
85-year- old 1000 times. Draw a straight line
on the logarithmic scale representing
exponentially increased risk (left graph) and it
just carries on across the age range all the way
from essentially five to 95. I've never seen
anything like that, it is quite extraordinary.
For school kids, five- to 14-year-olds, of 7
million in England and Wales, just three have
died – a 1 in 2.5 million risk. Meanwhile, 138
have died of other causes over the period of
the epidemic. So this is both a staggeringly
low risk, and very low compared to the
normal risk. But for people over 90, more
than 2 per cent, one in 50, have died with
covid. That represents about a one-third
increase over the normal risk they would have
had over this period.
The media have not been great always in
covering this. The “risk of dying from
coronavirus” is a very misused phrase. I've
been talking about what's called the
population fatality rate, the chance of getting
it and then dying. There's another risk, which
is if you get it, you die – the infection fatality
rate. It’s very easy to mix those up.
That happened when the UK Office for
National Statistics did a very good report on
risks for ethnic minorities. That's an
incredibly important issue. All the risks that
were discussed are the risks of catching it andDavid Spiegelhalter is Winton Professor of the
Public Understanding of Risk in the Statistical
Laboratory at the University of Cambridge, UK,
and author of The Art of Statistics, out now. This
is an edited version of a talk he gave at a New
Scientist event on 23 July 2020There are tricks, but it's not a
simple thing. A lot of it is feeling,
what I call “sniffing the number”.
My first question is always “why
am I hearing this number?”: to be
sceptical about the motivations of
the people telling you the number.
Are they trying to make it big or
small? Are they trying to persuade
me, rather than inform me? Almost
always they’re trying to persuade.
That leads to subsidiary
questions. What am I not being told
about? Can I believe this number?
Where does it come from? Does it
actually represent what I think it
represents? It's a bit like judging
fake news. You often can’t tell from
the claim itself; you have to look
outside and see what other people
are saying about it, do what’s
called horizontal searching. That’s
a very basic skill that you can teach
people. It's being taught in US
schools now to show people how
not be taken in by fake websites.
Sniffing out
the dodgy stats
In response to an audience
question, David Spiegelhalter
gave his tips for not being
blinded by numbersdying, and that includes the increased risk
of catching it that many ethnic minority
communities clearly have, because of their
jobs, or perhaps because of deprivation,
overcrowding and poor working conditions.
However, some reports had it that ethnic
minorities were 90 per cent more likely to die
if they became seriously ill with covid-19.
That’s not true.
We've done lots of experiments at the
Winton Centre, and we find that people have
got a complete misapprehension about covid
risk. Many people say, if I catch it, it's 50/50
whether I die or not. People are very anxious.
They really think if I get it, this is a very high-
risk situation. It is for some people, but for
most people, it isn’t, even if you catch it.
You can look at the actuarial risk of
dying in a given year. I produced a graph
back in March, before we'd had almost any
deaths in the UK at all, saying that the risks if
you get the virus are very similar to the risks
that are there anyway for dying in the
subsequent year. That means that if you get
the virus it roughly doubles your chance of
dying this year. I'd still argue that that's
roughly true. But I originally expressed this by
saying the risks from covid were about the
same as dying this year, which was very bad
communication, as some people interpreted
it meaning the death rate from the virus
didn't add to normal risk.
For a statistician, this has been quite a
stressful time. It's been great, but it’s been
hard work, and I’ve got things wrong. But a lot
of what we’ve seen is what I call number
theatre, a lot of numbers put out there to
impress people. This is not trustworthy use
of statistics. People delivering the statistics
should be proper professionals who know
what they're talking about, and they should
treat the public with respect.
Data literacy is a vital skill in modern life.
This covid crisis that made this even clearer:
not just in the ability to manipulate data, but
also to critique the numbers we are told. ❚Want to see David
Spiegelhalter’s full talk?
Sign up for the event on-demand,
including his answers to more
audience stats questions, at
newscientist.com/events