How accurate is the crime data?

First of all, it’s important to understand we only work with recorded crime data released by the Home Office. The actual level of crime which is often secretive by nature is usually estimated by the British Crime Survey, to be approximately 30% or so higher. Not all crime is pepetrated against human victims (e.g. property damage) and recorded crime does rely on human reporting. So closing the gap fully between reported and actual crime is a somewhat intractable problem but long understood.

Secondly, we are bound by the categorisation given to us by the Home Office of approximately 1400 criminal offences into 14 categories, so you don’t get the most precise insight. For example, not all violent crime listed here as violent is actually violent in terms of involving physical harm. It could be something like “Endangering Railway Passengers” or “Harassment” for the “Breach of a restraining order”.

Secondly, to give you some idea of numbers;

As at April 2014, we have 18,557,233 total crimes and ASB incidents in the database. These cover England, Wales and Northern Ireland – an area of some 40 million acres (Scotland is approx 19 million acres and the UK is 59). The total number of anonymised snap-points stands at 1,060,320 locations. So what this means is that any crime/ASB incident potentially happened between 1 metre and up to 2,560 metres away. However, most of the UK population lives at high urban density – seen from space, it’s still mostly a very green and pleasant land. And there is anything but an even distribution of people to landmass and the anonymised snap-points reflect this – they are not evenly distributed from each other according to area. Police.uk say that if a crime happened more than 20 km away from the nearest snap-point, it is not given a location – but this is extremely rare. Dots are never placed over specific dwellings. Often, the Home Office has allocated locations to key locations, such as railway stations and each map point has a catchment area which contains at least eight postal addresses or no postal addresses at all.

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