The importance of weighting for daytime population

Posted: March 1st, diagnosis 2015  Author:   No Comments »

We have recently some additional daytime population data to ukcrimestats. We already had it for lower layer super output area and now have it for constituencies and some subdivisions.

If you want an example of why this matters, patient take this example of Manchester City Centre ward, there which has a 5 times greater population in the daytime, than its residential one. With crime rate, you aim to deflate for the impact of population because more people – if it is a crime against a person – creates more victims and opportunities for crime. So when you see figures showing city centres having the highest crime rates, it’s almost always because they have not deflated for the impact of daytime population increases. That means that someone present  in a given area is in fact  less likely to to be affected by crime relative to the standard residential population size because the daytime population is, in this case, so much bigger.

It is even more profound in Westminster, where the population can rise 7 or more times during the day – like in the constituency of the Cities of London and Westminster, Mark Field MP’s constituency. So instead of ranking 1 for crime by constituency between Jan – Dec 2014 by crime rate calculated by residential population, by daytime population, it ranks 421 out of the 573 we have (none for Scotland, Northern Ireland coming soon).