Is Scotland’s police force really solving 60,000 fewer crimes?

“Statistics are like bikinis – what they reveal is suggestive, but what they conceal is vital.”

This quote – attributed to a Professor Aaron Levenstein – perfectly captures the dangers of making miscalculations, or generalisations, based on data sets.

When it comes to data, nothing is ever clear cut.

And ‘The Thinning Blue Line’ report released today by Reform Scotland, on how more Scottish police officers are solving fewer crimes, is a good case study.

Here, I pose and attempt to answer some key questions…

Is the report valid?

On the face of things, the report’s findings are correct.

On a per officer basis, the clear-up rate has decreased from 12 to 8 between 2006/7 and 2013/14.

The report argues this shouldn’t be happening when crime rates are falling, and there are now more than 1,000 additional officers to work on fewer recorded offences.

Are there issues with data?

There are a couple of problems I found when I quickly dug a little deeper into how the report presented the data.

Firstly, page 24 of the report details how there are nearly 60,000 fewer crimes solved in 2013/14 than 2006/7. But a mental eyebrow is raised if, for example, we look at how the homicide figure has been tallied. In 2006/7, 100% of 159 murders were solved – this compares with 102% of 108 homicides which were cleared up in 2013/14. Yet – despite a gold star for detection by Police Scotland – the report counts this as 51 of the “60,000 fewer crimes-a-year [which] are being cleared-up”. So despite a perfect clearance record, the police force is seemingly penalised for an overall drop in homicide. This is also the case for drugs where, despite an average 99% clear-up rate, the report claims more than 7,000 fewer drug offences have been cleared up by the force.

Secondly, the report correctly points out that the number of crimes cleared up increased by just 1% between 2012/13 and 2013/14. But if you look at the government’s individual crime categories, the clearance rates for robbery (+6%), rape (+11%), fraud (+4%), and attempted murder (+3%), increased significantly belying that overall 1% figure. Obviously I’m guilty of cherry-picking figures here (for example the clear-up rates of thefts from vehicles actually decreased by 4%) but it illustrates how generalisations can mask equally interesting statistics.

Are there other factors to consider?

One must also try and place these figures into context.

Surely more officers won’t necessarily equate to more crimes solved. Each crime should be taken on its own merit. What leads are there? What forensic evidence is left behind? What about crimes that maybe take more than one year to solve? What about the rise of internet crime and its online perpetrators who can be trickier to bring to justice?

And, as one freedom of information request that I submitted earlier this year shows, what about the average 58 officers who were on stress-related leave between April 2013 and December 2014? On paper there are more officers, but in reality a number were on the bench unable to work on solving crimes.

Are the additional police performing civilian roles?

The report makes assumptions, which may well be true, that any increases in unsolved crimes are due to more officers being placed into positions previously held by civilian staff – essentially taking officers off the streets.

However, the report doesn’t seem to have the data or proof to categorically support this claim, but rather relies on “Underpants Gnomes” logic (go on – look it up).

Indeed the report quotes Chief Constable Sir Stephen House in stating to Holyrood’s Justice Committee that “under the terms on which staff go, jobs are in most instances closed down, so in the vast majority of cases there is no backfilling [by police officers] to be done”.

So if backfilling is happening, how many officers is it really impacting? To what extent is this a permanent occurrence, or to just fill in to cover an occasional civilian staff absence?

If ever a freedom of information request could be used to strengthen an argument, this would be it.

Although to be fair, backfilling civilian or administrative posts with police officers was a point the government failed to address in its official response.