UNDERSTANDING CRIME STATISTICS
How Should We Interpret Crime Statistics
and How Can We Use Them?
What are the limitations of this data, and how must we interpret it?
SUMMARY (TL;DR)
The type of statistics one should examine depends on the specific question being addressed. Reported crime data—such as those published by Brzerk—can provide insights into which incidents have been reported and registered as crimes, how these figures develop over time, and the temporal and geographical context of the incidents.However, this data alone does not reflect the actual extent of crime. To gain a more comprehensive understanding, it must be supplemented with self-report studies and victimization surveys. (Sporre & Standar, 2006:51)
There are three important factors that should always be considered when interpreting crime statistics. These factors influence how crime statistics are compiled and presented across different countries:
- Statistical factors
- Legal factors
- Factual factors
These three factors can be seen as main categories, each with several subcategories.
Statistical Factors
Statistical factors include when statistics are compiled, crime counting methods, attempted crimes, the reference time period, and changes in statistical procedures. (Sporre & Standar, 2006:16)
Crime counting methods also affect the data. Some crimes involve multiple offenses. The country’s chosen method—either series counting or principal offense counting—affects the crime totals. Series counting registers each specific act as a separate crime, while the principal offense rule counts only the most serious crime in the incident. Sweden uses series counting, leading to higher reported crime numbers. (Sporre & Standar, 2006:17–18)
For example, “when statistics are compiled” refers to the stage at which a potential crime is entered into the statistics. In Sweden, incidents are recorded as soon as they are reported to the police, whereas in other countries, an incident might only be recorded once an investigation confirms that a crime occurred. This means Sweden tends to report a higher number of crimes, since not all reports result in confirmed crimes. (Sporre & Standar, 2006:17)
Attempted crimes can be treated as completed crimes, reported separately, or omitted entirely. In Sweden, they are mostly reported as completed crimes if they are punishable, except for homicide, rape, residential burglary, and car theft, where attempts are reported separately. (Sporre & Standar, 2006:18)
The time of recording refers to whether a crime is recorded based on the date it was reported or the date it occurred. Changes in statistical procedures—such as legislation or reporting practices—can also impact the number of crimes reported. (Sporre & Standar, 2006:19)
Legal Factors
These include differences in how crimes are defined or whether a crime requires a formal complaint (complainant-driven offenses) or is prosecuted automatically. For example, Sweden has a broader definition of rape than many other countries, which results in more acts being classified as rape. If a crime requires a complaint, it may not be recorded if the victim withdraws it. (Sporre & Standar, 2006:21)
Factual Factors
These refer to the legality principle, reporting willingness, and registration practices. The legality principle means police and prosecutors are required to accept a report if someone wishes to file one—a rule not applied in the same way everywhere.
Reporting willingness depends on individual trust in the justice system and other factors. Registration practices reflect how willing authorities are to formally record a report. (Sporre & Standar, 2006:21–22)
Reading the Statistics
Reported crime statistics include all incidents registered by the police, customs, or prosecutors as crimes—regardless of whether they later turn out to be actual crimes. This can result in overestimated crime levels. Attempted crimes may also be classified as completed, but some types, like attempted murder, are reported separately. (Sporre & Standar, 2006:30–31)
The purpose of crime statistics revolves around several questions, as outlined by Sporre and Standar in The Art of Reading Crime Statistics (2006):
"What crimes are recorded and how do they develop over time? What is done about them and what decisions do the police make? Who is suspected and how does that evolve? What do prosecutors and courts do with these crimes and suspects? What role does correctional care play? How many people reoffend?" (Sporre & Standar, 2006:50)
Again, depending on what you want to understand, different statistics should be used. Reported crimes (as discussed in this text) tell us what incidents have been reported and registered, but they don’t show the full extent of crime. That requires combining data with self-report and victimization surveys. (Sporre & Standar, 2006:51)
This is important because not all crimes are reported to the police, which means reported crime statistics don’t fully reflect reality. The difference between actual crime and reported crime is known as the dark figure of crime. The larger this gap, the less reliable the statistics are for measuring actual crime levels. (Sporre & Standar, 2006:66–67)
Sporre and Standar illustrate this relationship with a diagram. If the dark figure changes, reported crime no longer mirrors actual crime. But what affects this dark figure?
In their book, they mention that factors like the seriousness of the crime and the victim’s relationship to the perpetrator affect the likelihood of reporting. For example, crimes in close relationships tend to be underreported, while serious crimes committed by strangers tend to have higher reporting rates. (Sporre & Standar, 2006:69)
International Comparisons
Reported crime statistics are not ideal for comparing crime levels between countries, mainly because data collection methods vary. As discussed, statistical, legal, and factual conditions influence how data is collected and reported.
For example, Sweden’s broad rape definition and its use of series counting make direct comparisons difficult. Additionally, differences in when and how crimes are registered, whether attempted crimes are included, and whether the data reflects reported or confirmed crimes can significantly skew comparisons between countries. These variations mean that two countries may appear to have vastly different crime levels, even if the actual prevalence of crime is similar.
Instead of using national crime reports to compare international crime levels, Sporre and Standar (2006) recommend using the International Crime Victim Survey (ICVS). This survey asks identical questions across countries regarding everyday crimes, whether the respondent was victimized, and whether it was reported to the police. Because it standardizes both the questions and methodology, the ICVS provides a more reliable and comparable measure of actual victimization across different countries.
