White paper on crime 2012 Part5/Chapter3/Section1
Accurately identifying the situation with the occurrence of crime is essential as a premise to consider effective public safety measures within criminal policy. There are two methods available to identify it:  a method of totaling the number of cases reported to public institutions such as the police, etc. and  a method of conducting surveys using questionnaires, etc. to general public to investigate the actual conditions, type, and number of crime occurrences that will include the number of cases not actually reported to the police, etc. (dark figure). Information collected in the dark figure survey of  can only be successively compared with the reported number of  when conducted regularly. Both of  and  are indispensible to identify the situation of crime, and use of those two types of data as a supplement to each other will lead us to more effective criminal policy.
The importance of dark figure surveys has been recognized in major developed countries such as Europe and the U.S. for quite some time. Nationwide surveys have been conducted almost every year in the U.S. and the U.K. for over 30 years and are considered, along with criminal statistics, to provide important data to use in considering criminal policies. In addition, an International Crime Victims Survey (ICVS) commenced in 1989 for the purpose of international comparisons of crime victims has been conducted almost every four years in many countries/regions using a standard questionnaire. Over 300,000 persons in 78 countries/regions have participated in the survey to date.
In Japan the Research and Training Institute of the Ministry of Justice participated in the International Crime Victims Survey in 2000 and conducted its first Crime Victims Survey (dark figure) (2000 survey). The Institute subsequently conducted the survey every four years: the second survey in 2004 (2004 survey), the third survey in 2008 (2008 survey), and the fourth and latest survey in January 2012 (2012 survey; the survey was titled “Basic Survey for Creating a Safe and Secure Society”). A two-stage stratified random sampling method was used in each of the abovementioned surveys to select male/female subjects aged 16 or older nationwide, although the number of survey subjects varied. The number of survey subjects was 3,000 in the 2000 and 2004 surveys, 6,000 in the 2008 survey, and 4,000 in the 2012 survey. In addition, the 2012 survey was based on a mail survey (a method where a questionnaire is mailed to the survey subjects who are asked to return it after having filled in the answers), and thus differed from the previous three surveys that used the method of interviews being mainly conducted by visiting interviewers.