The Limitations Of Official Crime Statistics

The UK's official crime statistics are an inaccurate reflection of our everyday experience of crime, according to Dr Ziggy MacDonald of the University of Leicester, writing in the latest issue of the Economic Journal. His research shows that forecasts of crime trends fail to take proper account of what drives unreported crime. For example, someone who is currently unemployed is 7% less likely to report a burglary than someone who is currently in work, while someone on a relatively high income is 8% more likely to report a burglary than someone on less than average income.

That official crime statistics are plagued by what criminologists call the ''dark figure'' of unreported or hidden crime is reasonably well known, both among academics and in the wider community. What is not so well known is that under-reporting (or nonreporting) of crime is influenced by some of the same factors that are known to exert pressure on the amount of crime we actually experience in society. This is what MacDonald''s study shows, and it has serious implications for Home Office and academic forecasts based on economic models of crime.

The study shows that just as an increase in the unemployment rate is likely to lead to an increase in property crime, individuals who are unemployed are less likely to report being a victim of crime. The conclusion is that the forecasts of crime trends ought to include a mechanism for correcting for reporting behaviour. Otherwise, they do little more than predict what is happening to official crime statistics rather than what is happening to affect people''s everyday lives.

MacDonald's aim is to draw to the attention of economists some of the problems that are likely to be encountered when using official crime statistics in their analysis of the general crime problem. For example, data from the British Crime Survey reveal a remarkable variation in the percentage of crimes being reported to the police, with only 13% of robberies being reported in 1983 but 46.3% being reported in 1987. In addition to highlighting the general disparities between official crime statistics and the public''s experience of crime, the study also draws attention to differential police recording of crime, something that varies between police force areas and over time. For example, recent Home Office research suggests that the recording by police of vehicle thefts fell from 91% of reported incidents in 1981 to just 55% of incidents in 1995.

Having established that official crime statistics probably do not represent our experience of crime, MacDonald then investigates what this means for economic modelling of the crime problem. For some time, economists have tried to determine which factors influence the aggregate crime rate in society. These models, which typically focus on property crime, tend to show that in addition to being influenced by changes in the criminal justice system – for example, police clear-up rates or average sentence length – this type of crime increases when unemployment and the number of young men increase, but it falls as National Income increases. Recently, this type of analysis has been used by the Home Office as a basis for forecasting trends in crime.

What this study shows is that these forecasts have to be more sophisticated if they are to be of any real value to policy-makers. Using data from the British Crime Survey, MacDonald analyses the causes of under-reporting and shows that it is not necessarily a random event. For example, an individual who is currently unemployed is 7% less likely to report a burglary than someone who is currently in work, while an individual on a relatively high income is 8% more likely to report a burglary than someone on less than average income.

The overall conclusion of this analysis is that rather than fooling people all of the time with official crime statistics, politicians ought to be more careful. A more sophisticated public is becoming ever more aware that what really matters is what we experience in our everyday lives, not what the politicians tell us is happening.

''Official Crime Statistics: Their Use and Interpretation'' by Dr Ziggy MacDonald is published in the February 2002 issue of the Economic Journal. MacDonald is in the Department of Economics at the University of Leicester.