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NYPD Green? Visualising Police Spend in Selected International Cities

A Tableau dashboard showing three charts examining expenditure on police forces around the world.
One bunch of these things is not like the others.

The events currently occurring in the United States are at once only three weeks, barely six years, and 400 years in the making and do not have an easy resolution because of their manifold causes. One of the clearer roots of the problem is the wretched state of American policing, which has been in dire need of reform for longer than I've been alive; a rallying call of the 2020 movement has been "Defund the Police". I've not looked into police spending to know how much is too much, so I decided to do a comparative analysis of some American and international cities to see what their police budgets looked like.

Why did you select these cities?

Policing is quite complicated. I selected cities on the basis of their policing model being somewhat similar to American cities, which is that the police force is for that city (not the state or area), and that there is broadly one force doing the policing, and the systems of government are generally democratic (as in, no police states). This isn't a perfect comparison - there is often significant variation even within countries, such as France or the UK. However, some places deserve specific notes;

  • American cities have police departments but they are often within counties and metropolitan areas. This analysis focuses on the area covered by that police force, e.g. Seattle analysis does not include the Kings County Sheriff Dept.
  • A common refrain in arguments about policing refers to the legality of firearms in the United States. That situation is quite unique, but I included the PSNI in this data as while Northern Ireland is not a city, that force does have frequent experience handling crime involving firearms.
  • Hong Kong has been subject to major civil unrest for the last year. This loss of trust in the police from the HK locals and the planned changes in public security laws are likely to change the face of policing in the territory, but for now, it is acceptable to include.
  • This is just flat budget information, and doesn't include what the departments are spending it on. Certain cities and regions will have particular strains on their police budgets which may not apply to others - capital cities will often have to escort and police several thousand embassies and dignitaries for example.

OK, what did you find out?

A dashboard showing a set of three charts, demonstrating the funding difference between American and international cities.
Interact on Tableau Public here.

Americans spend a lot on their coppers, and it is notably higher than everyone else. It took me a while to work out what the best way of showing this as a comparison is, but I eventually settled on modelling budget and the number of law enforcement officers by population, and then looked at budget per thousand population for those cities.

One thing I particular like about the scatter plot is that while I could have used animation to switch between the panels, people who I asked to have a look at the chart generally went off in their own, different, exploratory directions with it, but called certain comparisons to mind;

  • Berlin and Los Angeles have similar sized populations and similar budgets, but Berlin has 7000 more officers than LA.
  • Hong Kong and Paris have lower than expected budgets for their population, but have way more officers than expected by the trend line.
  • Philadelphia has a similar population, budget and number of officers to the PSNI in Northern Ireland.

This is comparing a small number of cities so any model must be taken with a pinch of salt. The linear trend lines applied by Tableau do have significant P-values and suggest something interesting about the scale of difference between US and international cities - a city of 6 million people amongst the international group would have about 20,000 officers and a budget of about £1.7bn, while the same population amongst American cities would have about 26,000 officers, and a budget just over £3bn.

This analysis doesn't show where the money goes, which would be my next line of enquiry. The American police are distinctly more militarised than most other police forces, but I am not sure if that can fully account for the difference in spend.