What is the optimum size of a police force, either to be most efficient in tackling crime or most economically efficient? This is not a question of opinion, but of fact. Such things are determinable, and we have, between the UK and the US, which share most closely a model of policing, a sample set that includes forces such as the Met of 30,000 officers down to independent forces in small US towns of six to eight officers.
The 1960 Royal Commission on the Police in a very English way didn't actually rely on scientific or statistical method, but on ill-reasoned opinion that supported the prejudices of the Commissioners. Presenting the report to the House, the Home Secretary Henry Brooke said
The Commission suggests that forces numbering less than 200 are handicapped; that the retention of forces less than 350 strong is not normally justifiable, and that the best size of a force is upwards of 500 ... I agree with the Commission that in this small, densely populated island, we have too many separate forces...I am not suggesting that small police forces are inefficient; a small force can attain a very high standard of esprit de corps, but I agree with the Royal Commission that small forces tend to be handicapped. They lack the flexibility of larger forces; they cannot always make the best use of available manpower, and the efficient policing of wider areas is sometimes impaired by the preservation of what are often arbitrary and irksome police boundaries, from the point of view of crime and road traffic. Some areas are better policed by a large force than by a number of small forces, however efficient each of the small forces is.And there we have impeccable civil service Oxford logic, an argument bereft of fact or evidence and supported by reason alone. "We asked Charles, David, Neville and Tarquin and they all had a guess and we took the average and rounded it out".
Contrary to the Home Secretary's opinions, the job of the police is not to provide the Home Office with administrative convenience but to deal with crime - at least in the eyes of the public, whom the police serve and who pay their wages. Those efficient small local forces that caused the civil servants such irritation at the Home Office were exactly what the public wanted.
From the 1970s the economists and statisticians examined police structures. The academics found many factors that needed to be reconciled; night time populations, ethnic and socio-economic population composition, density, age profile of population - number of under-25s, density of businesses, road lengths and types, whether the area was growing or in decline, property values. As for the outputs, did one measure reported crime, arrests, convictions or just police interventions with no outcomes? One UK study (Drake and Simper 2002) even used the number of breathalyzer tests administered as a significant determinant of police efficiency.
However, what all of the many studies since the 1970s have in common, on both sides of the Atlantic, is that they quantify efficiencies in what police actually do - the entire panoply of police functions as they are constituted. As I will look at in the third of these posts, we need to look at policing differently.
A readable summary of the evidence is summarised in both a US study and a UK synopsis. The bottom line?
- The efficiency of a police force is optimised serving a population of 25,000 - 50,000 (US) or 25,000 to 250,000 (UK)
- There are significant and substantial dis-economies of scale - large police forces cost more and have more crime
- There is a lower level below which it is not efficient to maintain an independent police force - a population of about 2,000 citizens
Overall, cost of policing for England and Wales is £14.063bn per year. Mid-year population estimate 2018 was 59.17m. Annual cost per capita is therefore £237.67.
Just one note from the US literature review -
Whereas the average per capita expenditure for the 14 police departments in the sample was $177.36, Finney (1997) estimated that consolidating them into one department (with their arrest output remaining the same) would result in a per capita cost of $472.78.