The figures in the conviction statistics for minors and adults only partially convey criminality. Many offences are not reported to the police, not all offences are solved or end in a conviction.
Furthermore, with regard to the conviction statistics, not all sentences are recorded in the register of convictions. If a verdict is the result of a serious offence (felony or misdemeanour), it is, on principle, recorded in the register of convictions and therefore included in the conviction
statistics. If, however, a conviction is made solely on the basis of a contravention, then this is only rarely recorded in the register of convictions.
The conviction statistics do not, therefore, cover all convictions but only those due to the perpetration of a felony or misdemeanour. Under which conditions a verdict regarding a contravention is recorded, is legally determined in Art. 3 of the ordinance of 29 September 2006 on the register of convictions (VOSTRA ordinance).
Evaluation of the development of criminality
The VOSTRA ordinance was revised in 1992 and 2007. On each occasion, the changes had an impact on the number of convictions recorded in the register of convictions. For this reason, it is difficult to evaluate the trend in adult convictions from 1984 to 2015. It was therefore decided - in particular with regard to time series - to only take into account the verdicts made due to the perpetration of a felony and/or misdemeanour.
Despite the restriction to only these convictions, the evaluation of the development of criminality over time is only possible to a limited extent with the data from the conviction statistics. Victims' reporting behaviour can change over time, therefore influencing conviction numbers. Furthermore, the intensity of police controls may rise or fall depending on the priorities set. In particular in the area of road traffic and drug offences, such factors can effect the number of crimes reported and
thus influence convictions. The impact of revisions of laws and new forms of criminality should not be ignored either.
Completeness of data
Convictions are only recorded in the register of convictions once they are final. This can - in particular with serious offences - take some time due to appeals that may be made. For these reasons it takes several years until all convictions occurring in a given year are recorded in the register of convictions and appear in the statistics. The juvenile conviction statistics also contains only final verdicts.
This should be taken into account when interpreting data from the most recent survey years, in particular with regard to serious offence.