Outside the marginals

a commentary on the politics that followed the UK 2010 & 2015 elections

Do the Police “look like us”?

I have blogged previously about society’s preoccupation with ensuring that Parliament “looks like us” – when I would prefer parliament to represent the diversity of opinion within the country. Perhaps I am “male pale and stale”, but does that mean that Nigel Farage would represent me better than Diane Abbott?

Now we have statistics about whether the police “look like us”.

The case is slightly different to Parliament. Pictures of say, white policemen quelling a riot in a predominantly black area always looks bad – but even if racial diversity at “constabulary population level” was properly represented in the “force” quelling the riot, there would only be a few non-white faces and the pictures would look just as bad – and the non-white policemen may not welcome the attention.

But we have to be careful with statistics! Mrs May might find she has unnecessarily stirred a hornet’s nest.

Police forces in England and Wales do not represent the communities they serve and must increase ethnic diversity, …

Four forces – Cheshire, Durham, Dyfed-Powys and North Yorkshire – do not have a single black officer of African-Caribbean origin, Mrs May will say.

The forces do have some officers from other ethnic minorities.

But Mrs May will tell the National Black Police Association conference that the 43 forces in England and Wales are not racially representative of the communities they serve.

“We must ensure that the public have trust and confidence in the police, and that the police reflect the communities they serve”
BBC News Website, 22 October 2015 : Theresa May condemns lack of diversity in police forces

This sounds truly terrible. Let’s look at Durham – a county in which I used to live. Using data from police.uk:

Durham Police Ethnicity(data drawn from https://www.police.uk/durham/39/performance/diversity/ 22 October 2015 Open Government License v2.0)

The question is – based on the “visual” above, does Durham Constabulary “look like” the population it serves? Or do we go “shock horror! Durham does not have a single black officer of African-Caribbean origin”?

The same source offers a table of data for Durham:

 

Ethnicity Police officers Police officer % Force area population % Force area population
Asian or Asian British 8 0.70% 0.80% 5,114
Black or Black British 0 0.00% 0.20% 1,058
Chinese or other ethnic group 1 0.10% 0.50% 3,030
Mixed 11 0.90% 0.70% 4240
Not stated 0 0.00%
White 1,149 98.30% 97.80% 605,364
Total 1,161 100% 100% 618,806

 

If all other things were equal, what should be the chance that a single Durham Police Officer is “Black or Black British”?

Police Officers are drawn from a particular age demographic – and we don’t know this from the data. But let us assume that the age demographic is constant across all ethnicities.

So the chance that a single officer is black should be 1058/618,806 (0.17%) or the chance of not being black is (618,806-1058)/618,806 (99.83%)

The chance of 2 officers not being black is 99.83% x 99.83% or 99.83%² or 99.65%
The chance of 3 officers not being black is 99.83% x 99.83% x 99.83% or 99.83%³ or 99.49%
The chance of all 1161 officers not being black is 99.83% x 99.83% … 99.83% or 99.83%1161 or 13.71%

So the chance that none of Durham’s officers are black is about 1 in 7 – unlikely but not that impossible – based purely on population based assumptions. The chance is sufficiently unlikely that you might ask the question why?

  • Racially discriminatory recruitment policies
  • Racism within the force affecting retention
  • Prejudice on the part of black recruits unwilling to consider the police
  • Something else

From today’s headlines we seem to be invited to consider one of the first two options.

Let’s think about that “something else”. It will have to be hypothetical because the data is not easily available. The provided data indicates that there are 1058 Black or Black British people in Durham. It is probable that some of these people are foreign students on student visas (at Durham University or one of the FE colleges in the county). It is also possible that others are doctors or nurses from abroad – again on restricted visas. We don’t know the numbers, but for the sake of this example let’s assume that half of those 1058 are unable to consider a police career (and similar visa restrictions do not apply to the white population). Now we can examine how this hypothesis might affect the chances that Durham has no Black police officers.

The chance that a single officer is black would now be 529/618,806 (0.085%) or the chance of not being black is (618,806-529)/618,806 (99.91%)

The chance of 2 officers not being black is 99.91% x 99.91% or 99.91%² or 99.83%
The chance of 3 officers not being black is 99.91% x 99.91% x 99.91% or 99.91%³ or 99.74%
The chance of all 1161 officers not being black is 99.91% x 99.91% … 99.91% or 99.91%1161 or 37.05%

So the chance that none of Durham’s officers are black would now be about 1 in 3 – unlikely but quite possible compared to an expectation (based on the assumption immediately above) that in a force of 1161 officers we would expect 0.085% (or 1 officer) to be black.

Now apparently we hear that Durham does employ a black police officer (BBC News Channel 22 October 2015; 11:00 news bulletin)!

Lies, damned lies and statistics?


I picked Durham because I have previously lived there.

Looking at the other highlighted forces – Cheshire, Durham, Dyfed-Powys and North Yorkshire – Durham looks unfairly singled out.

The table below shows for BME (as opposed to Black and Black British) the number of BME officers and the expected number – based purely on ethnicity of the population served by the force.

 

Police force BME police officers BME police officer % Force area BME population % Force area BME population “expected” BME officers
Cheshire Constabulary 12 0.60% 3.10% 31,711 62
(-50 or 83% short)
Durham Constabulary 20 1.70% 2.20% 13,442 26 (-6 or 23% short)
Dyfed-Powys Police 8 0.70% 2.00% 10,400 23 (-15 or 65% short)
North Yorkshire Police 15 1.10% 3.40% 27,221 46 (-31 or 67% short)

 

 

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2 thoughts on “Do the Police “look like us”?

  1. For stats geeks:

    I say:

    The chance of 2 officers not being black is 99.83% x 99.83% or 99.83%² or 99.65%

    Since the situation is analogous to drawing balls form a bag (like the FA cup draw), the series is actually:
    (618,806-1058)/618,806 x
    (618,805-1058)/618,805
    which is:
    99.829025575% x
    99.829025298%
    Any error is in the 7th decimal place; I ask the geeks to forgive me for this simplification.

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