Per 1 000 residents: turning a count into a rate, explained simply
Two areas both have one pharmacy. One has 300 residents, the other 6 000. A plain count says they are the same. 'Per 1 000 residents' says the first is twenty times better served. Here is the formula, and the small-numbers trap it has to avoid.
One of them has 300 residents. The other has 6 000. A plain count - one pharmacy - says they are identical. Anyone queuing for a prescription knows they are not: the first is twenty times better served.
Per 1 000 residents is the one-step fix. Divide the count by the people who live there, scale it up to a thousand so the number is readable, and you have a rate: 3.3 pharmacies per 1 000 residents in the first area, 0.17 in the second. It is the most ordinary formula on the map and the one that changes the most maps, because nearly every “where is there a lot of X” question is really “where is there a lot of X for the people there”.
Per 1 000 residentsthe field's term: Rate
Pharmacies per 1 000 residents, read within a 10-minute walk and placed by rank so the whole spread of colour is used: brighter neighbourhoods have more pharmacies for the people who live there.
Switching it on
The map for “how much is here” is called Amount, and its Count as row is where a count becomes a rate. The same row sits on each factor of a score. Its default is “Total” - the count as it is. Change it to “Per 1 000 residents” and the number, the legend and the badge all switch to the rate.
Where to click
Map type
Amount
Pharmacy
Count as: Per 1 000 residents
The badge reads 'Per 1 000 residents · Rate' and the sentence under it, 'Pharmacy per 1 000 residents, within a 10-minute walk', is exactly what the map draws.'Count as' offers Total, Per 1 000 residents, Per km² and Share of its category. Options a metric cannot support are greyed out with a reason.
Why 1 000 and not 1?
Because 0.0033 pharmacies per person is unreadable. Per thousand gives 3.3, a number people can hold in their head and compare across areas.
Why is it greyed out for some metrics?
An average income or a share is already a per-something number. Dividing it by residents again is meaningless, so the app refuses and says why.
Reading the map
On the Single view the legend runs from the smallest rate to the largest. Hover any area and the card gives its rate; where the base was small, it also says the value was adjusted.
The legend spans the whole range London produces - here up to 64 per 1 000 in one unusual area, which is why the ranked map above is often easier to read than the raw ramp.One neighbourhood in south-east London: 0.4 pharmacies per 1 000 residents within a walk - the inspector below shows the numbers behind it.
The maths, honestly
Pharmacies per 1 000 residents in one area
Pharmacies counted
2
Residents
6 000
Divide
2 ÷ 6 000 = 0.00033
Per 1 000 residents
0.00033 × 1 000 = 0.33
The 300-resident area with one pharmacy gives 1 ÷ 300 × 1 000 = 3.3. Ten times the rate, from the same 'one pharmacy'.
Click any area and the inspector writes that division out with the area's own numbers, which is the fastest way to trust a rate you did not compute yourself.
The inspector's 'Show the maths' for that neighbourhood: 4.7 pharmacies' worth within the walk (nearer ones counting more), 12 560 residents within the same walk, and the 0.4 per 1 000 they make - followed by the method and its caveats.
The trap: tiny areas that shout
Here is what would happen without a safeguard. An area on the edge of a park has 3 residents and 1 pharmacy. The rate is 1 ÷ 3 × 1 000 = 333 per 1 000. It would be the brightest area in London, and it would be meaningless - three people prove nothing.
MapBees uses the standard fix from disease mapping, called empirical Bayes smoothing. The rule in one sentence: when an area has lots of residents, trust its own rate; when it has almost none, pull it toward the city's rate. The 3-resident area collapses to something near London's average; the 6 000-resident area barely moves, because it has real evidence.
The adjustment is declared, not hidden: 'where the base is tiny, the value is pulled toward the city's, so a handful of people cannot produce an extreme rate'.
What 'adjusted for small numbers' means on a hover card
It means the area's own rate was more than half replaced by the city's. Treat the number as “probably about average, we cannot tell” rather than as a measurement. Areas with nobody living in them show no rate at all - a pharmacy per resident in an empty park is not zero, it is a question that does not apply.
Rate versus density
“Per 1 000 residents” answers how well the people are served. Per km² answers how packed the ground is. Use the first for anything people need near home - pharmacies, schools, grocery stores; use the second for anything about footfall and competition on a street. And once you have a rate, the natural next question is whether it is high or low for London, which is the Compared to the average post.
Per 1 000 residents = count ÷ residents × 1 000. A count becomes a rate you can compare across areas of any size.
One pharmacy for 300 people and one for 6 000 are not the same. The rate says so; the count cannot.
Tiny bases are pulled toward the city's rate and flagged as adjusted, so three residents cannot light up the map.
The Single view shows the raw rate on a lowest-to-highest ramp; in a score the rate is placed by rank, which spreads the colour.
Click an area and 'Show the maths' writes the division out with its real numbers.
Quick questions
What does 'Per 1 000 residents' do?
It divides a count by the number of people living in the area and scales it to a thousand, so 14 cafés among 1 660 residents becomes 8.4 cafés per 1 000 residents - a number you can compare across areas of very different size.
Why per 1 000 and not per person?
Because 0.0084 cafés per person is unreadable. Scaling to a thousand gives numbers like 8.4, which people can hold in their head and compare.
What happens in an area with almost nobody living in it?
One ATM among three residents would be 333 per 1 000 - nonsense that would dominate the map. MapBees adjusts for small numbers: where the base is tiny, the value is pulled toward the city's rate, and the area is flagged as adjusted.
Why is 'Per 1 000 residents' greyed out for some metrics?
Because some metrics are already rates (an average income, a share). Dividing a rate by residents again gives nonsense, so the option is disabled with a reason.
What does 'Rate' under the badge mean?
It is the field's own term for a count divided by a population. MapBees leads with the plain words, 'Per 1 000 residents', and shows the term beside them for anyone who wants it.
See it on a real map
The best way to understand the score is to play with it. The full app is on a free tier, with no sales call.
Builds MapBees's location-intelligence pipeline end to end — census and Overture Maps ingestion, H3 hex scoring, and the map interface — and writes the methodology behind every number on the site.
