Methodology - Crime and criminal justice


How are crime statistics put together?

Traditional statistics and scientific studies are often based on survey data and methods such as sampling, interviewing, or measuring, followed by statistical estimation. In contrast, the official crime figures are based on each country’s records made for law enforcement, investigation, prosecution, court cases, and prison administration. This affects how the statistics turn out.

The basic data is produced by several different authorities, such as the police, prosecution, courts, and prisons. Each authority makes the records primarily for their own purposes, so the data and methods they use may vary.

Each country establishes its own criminal laws, defines crimes, and governs legal proceedings and justice reactions. For these reasons, the basic data and how it is collected are different in each country.

What does this mean for users of crime statistics?

These differences mean it may not be relevant or valid to compare figures between authorities or between countries. For users of crime statistics, this means directly comparing figures between countries may result in misleading inferences or wrong conclusions.

The records for individual crimes or criminals are not sent to Eurostat. Each country sends tables containing official statistics, in practice summary figures for various categories. That means Eurostat does not have detailed information that could be used for further analysis. Eurostat therefore asks each authority in each country for additional information on how the figures are made. It then presents this information alongside the country’s tables, but does not use it to adjust the figures.

Crime figures can only be fully compared between countries that use the same crime classification. To make statistical figures, the criminal acts are counted by each type of crime. These types can be defined by a common standard, namely the International classification of crime for statistical purposes. It groups all types of crimes for statistical, rather than legal purposes.

Links to more detailed information