Maths : help me out here

[wizzler]

Be gentle please .. I'm obviously missing something .
According to the BBC 91% of people aged over 12 have had their first jab.

When I look at my home town using their "see the numbers where you live" we are at 79%. I've looked at a few cities and no one is anywhere near 91 %

So surely that means that if all the towns I've looked at are below 91% then somewhere else must be higher than that if the total percentage is 91%

Is my logic flawed or are there pockets of population where close to 100% have had their first jab

What is the % first jabs in your neck of the woods ?

... and/ or could someone explain to me why my maths is skewed?

88% for my area so quite close to 91%

Is the 79% a percentage of total population or of population over 12?

Both stats are population over 12. As far as I can see I'm comparing like with like

More or less did an episode on this a few months ago. I forget the details, but basically the local figures and the national figures use different sources for the population. I think one may have used the national survey, and one GP registrations? I forget the details. But there was a reason, and it's basically that you, through no fault of yoru own, aren't comparing like with like.

Thanks @Motorina . I love More or Less I shall hunt down that episode tomorrow

A) cities have lower %s than rural areas so if you're looking at cities that's what you'll see
B) more interestingly, the population estimates for the country as a whole come from a different source than the population estimates for local areas. There's double counting in the local area populations because people move and stay registered in two places. Therefore since the number of people vaccinated is a known fact, an overestimate of the population size leads to an overestimate of the number of people unvaccinated. So yes, all of the individual regions report percentages vaccinated that are lower than the percentage unvaccinated for the whole of England, which is as you say, mathematically impossible.

This was the episode. It was in the context of discrepancies in Cambridge figures: www.bbc.co.uk/sounds/play/m000wsf0

And my pleasure - i'm a More or Less geek too.

I think it's because the most reliable population estimates at national level are the ONS ones. But at local level they're not so reliable so they use the data from people registered with GP practices. These include quite significant numbers who've moved abroad and not deregistered with a GP, so are considerably higher than they should be particularly in areas with an internationally mobile population. Overestimating the population makes the proportion vaccinated appear lower than it really is

91.2%of over 12s where I live. Rural area.

A lot of scottish local authority area are over 91%.....Highlands, Orkney, Shetland, Aberdeenshire, Perth & Kinross, Borders....although relatively low population areas if they're calculating the % as a percentage of the national population and not averaging the percentages in each area.

Very rural areas have less fluid and international populations so their headcounts are more accurate. By contrast London in particular probably has low vaccination rates but probably not nearly as low as the headline figures would suggest.

My MSOA is up to 92.1% first dose
87.7% 2nd
73.5% 3rd or booster.

Slightly lower for the LA as a whole so there must be areas with much lower numbers

There was a thread on here with people saying they had moved abroad but were still being counted in their GPs list as a patient so they were vaccinated but just not in the UK so made the % lower than it should be.

Only 68.7 in my local area. Boosters only 40.