A really great post has been brought to my attention on a blog I wasn’t previously following, and I’d like to share it with readers here. There are two current bugbears at the moment causing me irritation that anyone who follows me on Twatter will be aware of. The first is the woeful, shambolic nature of the local railway, and it’s use of performance figures. The second is the use of statistics by Walsall Police Superintendent Keith Fraser.
On the surface, neither of these are interesting or worthy of note, but as a self-confessed statistics monkey, I beg to differ. Most folk don’t understand the weight and bias that can be subtly and effectively applied to numbers in discussion, and many who quote numbers that look appealing don’t understand how easily they can misrepresent things.
London Midland Trains, currently experiencing large numbers of cancellations and service alterations due to staffing issues, tweet performance data daily. They do this for the whole network as one figure. By amortising every single train from every line, this neatly disguises poor performance hotspots like the woeful Cross City Line, by tying them onto solid runners like Stourbridge Town – Junction. Further, it was recently pointed out by one clued up Network Rail employee that on one Thursday, London Midland avoided 44 cancelled services being counted in their performance stats by filing their removal as short-notice timetable alterations, which can be registered up to 10:00pm the night before they’re due to run. They can legally omit these from performance stats.
When called on the matter, London Midland moved to include those cancelled services in future figures, but still won’t give line by line performance, or supply data measured at peak times in isolation.
Since challenging Superintendent Fraser weeks ago, the situation I previously highlighted with police statistics he quotes has moved no further forward; I was asked to mail his press office with my concerns, which I did. I’ve never been dignified with a reply, and now it is being insisted that I telephone him in person. There seems to be no will to understand or comprehend why certain figures cannot be quoted as absolutes. It doesn’t take a detective to work out that I’m being fobbed off.
To Superintendent Fraser, I will point out that I don’t do deals in private, and anything said on this matter can be discussed openly, and in public. This is, after all, about transparency.
On the whole, I support Walsall and, by extension, West midlands Police. But statistics like the above one are a good illustration of why data awareness is so desperately needed. The above figure is calculated by calling back complainants and surveying their opinion. This represents a specific group, and leaves out those who fail to get service from the police in the first place. The data quoted is therefore misleading.
For an organisation that claims to be reforming away from a reliance on arbitrary statistics, this is quite depressing.
In their ‘About Us’ piece, West Midlands Police assert:
Traditionally, police forces have measured how they are performing by purely focusing on crime data – how many offences have taken place and if crime has gone up or down.
From April 2011, West Midlands Police took the decision to move away from this sort of counting and introduced a new way of judging its performance against a framework based on what the public tell us they want from their police service. This new way of measuring our performance is based on our vision, our values and the behaviours we expect of staff.
It is hugely important that numbers quoted in public discourse are easy to understand, traceable and carry veracity. They should also be, as far as is possible, presented in an impartial manner. All I’m asking of both Walsall Police and London Midland is to issue full datasets of such numbers they quote, preferably made available online. These datasets need to be accompanied by explanations of how they’re gathered. Many public bodies do this. That way, we can fact check the numbers we’re being told, and decide if the use to which they are employed is fair and accurate.
It is therefore with a degree of trepidation I commenced reading Inspector Guilfoyle’s blog post about misleading and pointless data and it’s visualisation. However, what I found was a clever, solid and intelligent demolition of nonsense numbers. In short, it’s a brilliant read and I commend it to anyone, not just numbers geeks like me. I tip my hat to the Inspector, and hope and pray he might have a word with his colleagues and try and improve statistics literacy in Walsall. Lord knows, someone needs to…
Statistics don’t lie. People who quote them, however…