Stats and graphs - % or raw numbers?

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These didn’t post - sorry

Oops- yes they did - retires in confusion

First of all, yes, you do have it arse about tip. 100 in 1000 is one in ten. Imagine them all standing in a row, and then one in every ten stepping forward. There would be a hundred in the front row.

I haven't read the rest of the post yet (just sitting down to breakfast) so won't comment on the rest.

Totally agree, lots of figures have doubled etc. sound bites around. It takes a bit of digging to understand the situation.

I wonder how many days/weeks before we have a new variant (epsilon I guess will be it’s given name) another excuse to keep restrictions in place.

(Totally unrelated, in my little corner of the world there has been an obvious downturn of mask wearing this week, maybe heat or maybe folks are rebelling?)

Hope you’re sitting down Maw, we’re going to agree again

First, 100 cases in a village of 1000 people is 10,000 per 100,000, that would be disastrous.

Whitty et al are very good indeed at using their graphs to get across the message that they think is important. I don’t blame them for it, but it is manipulation. Some people can look at the graphs and say “yes, but…” while others just see big rises. I actually took heart from the slides on Monday because it showed that the biggest rise in cases and hospitalisations is in the unvaccinated population. Not great for them, but it means that as we get them vaccinated things should get better, which is why I support a pause in easing until we get that done.

On the other hand, although numbers are low at the moment they could go up if we don’t take action, so showing the relative size of cases today compare with during the second wave could make people complacent.

I don’t agree with the lies, damned lies and statistics thing. There are lies, damned lies and people who are good at using statistics to get their message over

You’re right about one thing though. My DGD’s school had one case, and isolated the class. A few days later it emerged that another child (same class) had tested positive. That’s 100% increase in cases! If you don’t know the raw figures, percentages are not really helpful.

If numbers double every two weeks, it takes just fourteen weeks for 10 cases to rise to 1280. The rate of change is what matters. If number double every week, you could have 1280 cases in seven weeks.

Two cases one month, then four the next means the number of cases doubled. In statistical terms doubled is a rise of 100% on the figures of the previous month , so that would be correct for that area and those dates. If you add "from 2 to four" into the statement it becomes clearer to the 99% of us who can't "see" a statistic.

With the 95,172 for Jan 1 to 28, and the 2,851 for May 6 to June 16, they could highlight ( with computer technology) the two figures and the two points on the graph and add something like "This is much better than that, but it is more than last week, and we don't want that rise to continue or we will be into another peak" or some such thing. It is true that with a more infectious variety, more people are potentially cathing it from each case, so any rise in one week could be even bigger the next - if it were doubling each week it would go 1, 2, 4, 8, 16, 32, 64, 128, 512, 1024 2048 and so on.

However, I am not sure Boris understands statistics either, and whenever a scientist has tried to tell us the unvarnished truth, he gets howled down and called a doom-monger.

An example of scientsts telling the unvarnished truth...

One member of independent SAGE told us that there would be a huge number of deaths and hospitalisations this summer based on the infectiousness of the delta variant and the number of unvaccinated people. I can't recall the peak number but it was based on 7 million people becoming infected between now and the end of July, I think. Could happen.

Only 4 1/2 million people in the UK have been infected since the start of the pandemic. As well as the axes of graphs, we need to know the starting assumptions as well.

Elegran

First of all, yes, you do have it arse about tip. 100 in 1000 is one in ten. Imagine them all standing in a row, and then one in every ten stepping forward. There would be a hundred in the front row.

I haven't read the rest of the post yet (just sitting down to breakfast) so won't comment on the rest.

So isn’t 100 in 1000 the same as 1= in 100,000?
I said we have a population of 1000 so to achieve a stat of 1 in 1000,000 wouldn’t you times the 1 by 100 ?

Feeling really dense this morning- blame Chris Whitty! ???

Umm 4.5 million have had a positive Covid diagnosis.

It’s a bit different from 4.5 million have been infected??

Yes, I agree Peasblossom.

100 in 1,000

is the same as 1,000 in 10,000 (times both sides by 10)

is the same as 10,000 in 100,000 (times both sides by 10 again)

I really did get that the wrong way then? If the population were 100,000 we would need 400 cases to achieve the same stat?

Might be best to give up teaching me Higher Math ???

For a village of 1,000 people to have a stat of 1 in 100,000, 0.01 people would have to have a positive COVID diagnosis.

You can see why I prefer raw numbers! ?

Now I'll really confuse you MawBe. The stats usually given are the number of new cases in a given time and the incidence rate per 100,000, ie the number per 100,000 who are infectious at any one time. People are infectious for longer than a day, so the incidence rate and the new cases aren't the same.

Example:

Day 1: 1 person tests positive. Over the course of the next couple of days, it's likely that one person will infect at least another two people, if no steps are taken to self-isolate.

Day 8: 2 people have now tested positive, but the original person has (hopefully) recovered, but possibly not, so there could be two or three people still ill. The two new people will probably infect another 4 people.

Day 15: At least 4 people will be infectious. The previous cases will no longer be infectious, but they could still be ill and possibly need hospitalisation.

In a village of 1,000 that would be an incidence rate of 400, which would be high.

The trouble with raw numbers is that you can't compare areas. Four cases in your village would be high. Four cases in London would mean almost nothing.

Think I’m coping!