Screening out crimes in London

Nigel Williams, 18 July 2013

The concern

When Sir Bernard Hogan-Howe moved from Liverpool to the Metropolitan Police in 2011, he advocated a reduction in the number of crimes screened out, that is put aside as having little chance of detection and conviction, relative to the size of the damage.
Roger Evans, a conservative on the Greater London Authority, has challenged the Metropolitan Police on progress. He discovered that some categories of crime were still screened out in an alarmingly high proportion of cases. Even so, wishing police to pursue every case to a successful conclusion risks demanding an enormous waste of scarce resources.

Differences between crime categories

The different categories in the screened out rates have different stories behind them. Possession of Drugs was only screened out in 114 cases out of almost 50,000. Immediately the crime has been recorded, the perpetrator has been identified and the evidence collected. Handling stolen goods is similar. Only 12 cases were screened out, for a crime which many victims will be happy to see resolved. ‘Going equipped’ or possessing an offensive weapon also have the advantage that the evidence is usually there at the time of recording. All these categories of case carry automaticlly high detection rates, giving making them appeaing to a target-driven culture.

Serious offences get the full treatment. It is comforting to see no murders and only one recorded rape in the ‘screened out’ column. Police are required to give reasons for taking a case no further.

Preferred sources of evidence

Evidence counts for a lot. A vital difference between theft from shops (29 per cent screened out) and theft from motor vehicles (86 per cent screened out) is that shops make use of security staff and CCTV so that there is at least a starting point for the investigation.

Potentially, there is extra evidence that can be brought to bear on some burglary cases. For example, a complaint against Google’s Street View product was that it gave burglars the means to seek out suitable premises unobserved. Now that it is understood how easily browsing data may be passed to security agencies, there is potential for police to analyse who has been using street views of a burgled neighbourhood. This would require a compromise, sacrificing a degree of browsing privacy for an increased chance of catching some burglars.
Nevertheless, it is important not to rely always on the same easy sources of evidence. It would be invidious to have two neighbourhoods where only the one with a CCTV camera ever had its burglaries investigated. The police need regularly to review their preferred sources of evidence to increase the proportion of cases worth pursuing.

Need for extra officers

The Metropolitan Police had approximately 32,000 officers in 2012, with other duties besides detection. In 2012/13 they screened in 424,000 cases and screened out 347,000. It means that the average officer’s caseload of screened-in crimes was in the tens not the hundreds. Following up 45,000 more burglaries, 75,000 more thefts of or from motor vehicles, 37,000 more cases of criminal damage and 150,000 further thefts would need several thousand extra officers. As these would generally be the cases with less to go on, there would not be a commensurate rise in the number of detections. The categories with high detections rates are already mostly screened in.

Repeat offenders

Even if close to half the burglaries fail the screening process, the knowledge that most offences are committed by repeat offenders means that the criminals do not remain uninvestigated for long, and even their screened-out crimes may eventually be solved by being taken into consideration. The ideal is that each offence should be solved immediately but the cost would involve diverting officers from chasing criminals to chasing wild geese.

Conclusion

Screening out is not contrary to good policing. It does involve the admission that some crimes are beyond the resources generally allocated to address them. Perversely, studying the proportions does send a message to criminals about which crimes have the best chance of avoiding detection. The positive effect of collecting the screening- out data is that police forces receive a signal how they need to redistribute their resources to reduce the overall harm done by unsolved crime.