Data, damned data and statistical data bases

Scotland Yard released statistics showing a 6% fall in crime in a year and an 8% fall in violent crime. But the study, written in February by the Metropolitan Police Authority, warns that the safety of the public and police officers could be "compromised" and says potentially violent young people "slip through the net". It also throws into question claims by Mayor Ken Livingstone that there has been a "dramatic" fall in crime - a key plank of his campaign for re-election.

Rival Brian Paddick, the Lib-Dem mayoral candidate and a former senior Met officer-is reported as saying "This report is clear evidence of what I have been saying all along - that police-recorded crime statistics don't reflect the true picture."

The report says that although the Met's "central policies "are to count crime honestly, "borough commanders and senior management team members are constantly dealing with the tension between recording crimes accurately [and] the ongoing pressure from central government to meet crime reduction targets".

As a result, some parts of the force have adopted "local policies" to create "obstacles stopping victims reporting certain crime types".

For example, some police stations refuse to allow victims of mobile phone theft to report the crime unless they can quote the phone's IMEI serial number,the 15 digit code found by typing a special code into the handset. Most people are unlikely to have recorded the number, if they even know what it is, so the figures for theft look better.

Mobile phone theft,  account for 28% of all thefts and is a particular problem for children and teenagers, was the subject of a government crackdown last year. Then home secretary John Reid said: "Being robbed for your mobile is a harrowing and distressing experience that has happened to far too many of us and our children. We are determined to stamp this out." Phone crime has fallen since then, but it is not clear how much of this is due to statistical manipulation.

The report says officers and staff in the Met's "crime management units", who are responsible for recording crime, "have been pressured to make decisions that they felt were dishonest". It found "specific incidents where pressure was applied... that affected the accuracy of the crime-recording process".

"The focus on priority crime... can create a perverse incentive to record crime inaccurately, eg for robbery and pickpocketing to be recorded as theft," says the report. The official figures show that robberies in London have plummeted more than 20% in the last year: thefts have fallen by much less.

The report notes "The current system requires officers to spend more time administrating than investigating." Data is stored on a variety of often obsolete and incompatible computer systems and "often has to be entered several times on different systems, increasing the likelihood of mistakes".

Referring to the teenage violence outbreak which has claimed 13 lives this year, the study says that "poor" data recording "inhibited the identification of young people at risk of escalating criminality". As a result, youngsters "can slip through the net when committing lowlevel offences, only coming to the attention of the police when their offending has reached more serious levels".

It says "inaccurate crime recording" could lead to "compromised officer and public safety" because police do not have a complete picture of crime: "The Met cannot tackle crime properly if they do not know what is happening and where."

The report, called Crime Data Recording Scrutiny, is based on Met documents, interviews with the force's management, including Deputy Commissioner Paul Stephenson, and questioning officers who compile crime figures.

Source: http://www.thisislondon.co.uk/