By analysing the number of crimes recorded by the police in a given time period and in a particular geographic area, changes in crime levels over time can be tracked. The significance of the trends will depend on how much data is available: the higher the numbers being analysed and the longer the time period, the more accurate the trends are likely to be (Louw, 2001).
Police data can be used to compare crime rates in different suburbs, cities, provinces and countries. However, in each area police statistics must be supplemented with data on population size, the number of registered vehicles, or the number of stock owned, depending on the crime types that are being compared. This is the most accurate way of comparing crime between two areas because it takes into account the potential for victimisation. It is inaccurate to compare the raw number of murders in Perth with those in London, because there are many more people living in London. This means the potential for murder is much higher there than in Perth (Bottomley, & Pease).
The police record a range of details about when and where crimes occur, who the victims are and, when they are known, who the perpetrators are. In some cases information is also recorded about the types of weapons used, and other factors such as the use of alcohol or drugs by the victim or offender. This information helps to determine whether, for example, most assaults are related to alcohol consumption or if the number of murders committed with a gun is increasing (Louw, 2001).
Official crime statistics, like that gathered through any other means, has its limitations. It is ultimately the responsibility of those who use police statistics to be aware of these inconsistencies and make an effort to include them in their analysis of crime. Because the police depend on the public to report offences, it is unrealistic to expect the police to have information about all crime (Louw, 2001).
Crime types that are typically under reported include petty theft, fraud, corruption, sexual assault and crimes against children. Victim surveys which ask a select sample of people in a particular suburb about crimes they have experienced over a specific time period, can supplement police data to fill some of the inconsistencies within the recorded statistics ( Bottomley, & Pease, 1986).
On their own, police statistics do not show what causes crime. These statistics, like those gathered through victim surveys, indicate trends and areas for further investigation. For example, an analysis of the number of murders recorded on a monthly basis shows a consistent and dramatic peak over the Christmas and Easter holiday periods. This shows that murder may be related to the gathering of people, friends and family over holiday periods, together with the consumption of alcohol. The police statistics however only show the increase in the crime not the reasons behind the increase (Maguire, Morgan, & Reiner, 1994).
One way of assessing whether police statistics are valid is to compare them with victim survey results. This enables a check on whether crime levels are increasing or decreasing as per the official data, and the extent to which police figures reflect the range of crimes being committed (Louw, 2001). Through community surveys it has also been determined that most victims of crime only report it if they believe it to be serious enough otherwise the crime remains unreported which distorts the police statistics. Victims are more likely to report such crimes as hijacking, vehicle theft and murder, whereas crimes such as sexual offences and petty theft were more likely to go unreported by more than half of the victims.
Once the public have reported a crime, how the police handle the information can affect the reliability of the crime statistics. The problems that can affect the statistics often occur at station level through either human error, or through the lack of time allocated to record the information correctly (Louw, 2001). The reliability of the statistics can also be affected by technical problems, the complexity of the system, the enormity of the crime database, network difficulties, computer downtime, or faulty programs.
Extensive research has been conducted on the reliability of official crime statistics with conflicting results. On the whole most conclude that police statistics are reasonably reliable when interpreted correctly with the use of victim surveys as corroboration. However there is a small minority that conclude that due to the gradual shift of policy towards performance based policing, statistics have become less reliable as police now have targets that they have to reach each month with crime clear up rates, which they believe leads to the distortion of the data (Louw, 2001).
Furthermore the research indicates that police operations that target one specific crime or one specific suburb may reduce the crime rate in the short term, but over an extended period this action will only lead to the distortion of the statistics.
Crime Statistics rely on reported crime and due to this crime rates are also reliant on reported crime (Louw, 2001). In conclusion it is clear that crime rates and crime statistics have to be viewed sceptically but not disregarded as unreliable because with proper recording and objective interpretation plus the use of community surveys on crime, these statistics can be a useful tool in the continuing fight against crime and criminal activity within society.
References
Bottomley and Pease. (1986). Crime and Punishment - Interpreting the Data. Open University Press.
Louw, A. (2001). Figuring it Out: Getting to Know Police Crime Statistics. Nedbank Iss Crime Index Volume 5 Number 3 May-June.
Maguire., Morgan., and Reiner. (1994). The Oxford Handbook of Criminology. Oxford - Clarendon Press.
