The limits of the crime rate metric – only use with hefty caveats

I’ve written about this before but it’s worth pointing out again. There are real shortcomings in trying to compare different areas by crime rate. It really doesn’t give you a clear picture and leads to huge distortions.

So what is crime rate again you say?

Crime rate is measured by the number of crimes in a given area for a given period of time per 1000 residents.

The key point here is that crime rate would be more meaningful if residents in said area actually didn’t leave their area, to go shopping or to work etc. If people did that, then the daytime and nighttime population would be exactly the same as the residential one. If everyone stayed put in their homes, crime rate would be an excellent metric. Obviously that never happens. Now I think about it, it was probably most useful during the lockdown, when daily movements were at a historical low.

Typically, crime rate tends to skew regional crime statistics to city centres, where day and night time populations can be up to 10 times higher the residential population. That’s why Westminster  and Oxford Street in London or very near to it, tends to figure so prominently as the areas and street with the highest crime rates across the UK. Last month it was Argyll Street, just round the back of Oxford Street with the most incidents – but I suspect due to the anonymisation moving crimes up to 400 metres away from where they actually happened, many of these crimes actually happend on Oxford Street or the shops around there.

But anyone who walks up and down Oxford Street knows that even on a quiet day, it’s a sea of humanity, with many thousands of people at all time crowded into a small area. That means that statistically, because there are so few actual residents in the area, it has a huge crime rate, but your chance of being a victim of crime either as a resident or a visitor is actually pretty small. Personally, I’ve never felt unsafe there.

So what should you use alongside crime rate to get a full picture?

For comparing areas that vary in shape, size and population, like constituencies, wards, postcode districts and sectors, I would recommend trying “crimes per hectare” or “crime rate per hectare” – both of which are uniquely available on UKCrimeStats – we invented it and you can run reports from UKCrimeStats ranking all different shapes on that basis. Sign up here.

For postcodes, this is far easier because each postcode comes with a fixed “centroid” which is a latititude and longitude coordinate. We have caculated crime totals and crime rates with 3 different radiuses of 0.25, 0.5 and 1 mile around each of the 1.7 million postcode centroids. You can either buy all of that data from here – postcode radius files, or if you want a nicely formatted and clear report for each postcode delivered to you online right now, buy a report from us.



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