Crime and reactions to crime in 34 Swedish birth cohorts: from historical descriptions to forecasting the future

Abstract

This article analyses 34 Swedish birth cohorts with regard to their participation in crime as measured by data from the convictions database maintained by Statistics Sweden. Most existing cohort studies are limited to one or a few cohorts. By contrast, the present study includes 34 cohorts, i.e. all persons born in Sweden between 1958 and 1991. The article discusses methodological problems associated with this type of approach and examines the possibility of making forecasts. The central results are that the number of males with a criminal record has decreased, whereas the number of females has remained fairly stable. Forecasts indicate that the cohorts' participation in crime will continue to decrease. Research and policy implications of the findings are outlined. It is proposed to introduce cohort statistics as a standard branch within regular criminal justice statistics.

Keywords::

• birth cohorts
• crime
• crime drop
• criminal statistics
• forecasting
• Sweden

Acknowledgements

The idea of Swedish cohort statistics was developed by Leif Lenke during the second half of the 1970s, a task he was commissioned to perform by Statistics Sweden. It was also Leif who noted the value of following up not only youths, but also adults. Leif Lenke passed away in 2008. He would otherwise have been one of the authors of this article. I also wish to thank my colleagues Christoffer Carlsson, Felipe Estrada, Henrik Hellborg, Anders Nilsson, Jerzy Sarnecki, David Shannon and Henrik Tham for their valuable criticism and advice.

Notes

¹ Early Nordic examples include studies by Groth (1947), Christiansen (1961), Møglestue (1965) and Knudsen (1973).

² The ‘Offenders Index’, which constitutes the basis of the UK cohort statistics, appears primarily only to have been utilized by Keith Soothill and colleagues (see, e.g. Soothill, Francis, & Fligelstone, 2002; Soothill, Ackerley, & Francis, 2004a, 2004b, 2008; Liu, Francis, & Soothill, 2011). There are no corresponding Swedish studies based on the database maintained by Statistics Sweden.

³ Cohort statistics can be produced even in the absence of personal identity numbers, as is exemplified by the UK cohort statistics (for a description of the procedure employed, see Ministry of Justice, 2010, p. 13). Personal identity numbers facilitate the work a good deal, however (Lyngstad & Skardhamar, 2011), and are the reason that it is possible to produce Swedish cohort statistics that include all cohorts born during the period 1958–1991.

⁴ That is K[N]_t = K[N]_t − 1 × K[N+1]_t/K[N+1]_t − 1, where K[N]_t is the sum of the number of individuals in cohort N with a first conviction at age t. N = 1959, 1960, …, 1990, 1991 and relates to the birth year of the cohort; t = 50, 49, …, 19, 18 and is the age of the cohort members.

⁵ Even when parametric estimates are employed, the breadth of confidence intervals increases quickly in line with the number of years that needs to be estimated.

⁶ The threshold was chosen ad hoc and has no theoretical basis. It was simply chosen since it has been used in other Swedish studies.

⁷ That is individuals (net) in the cohort statistics and in self-report surveys, individuals (net or gross) or households in crime victim statistics, number of offences (gross) in statistics on offences reported to the police, individuals (gross) in convictions and prison and probation statistics and individuals (net) in recidivism statistics.

⁸ Compare Quetelet, who as early as the 1830s (1835/1842, p. 6) noted that ‘Society includes within itself the germs of all the crimes committed, and at the same time the necessary facilities for their development. It is the social state, in some measure, which prepares these crimes, and the criminal is merely the instrument to execute them. Every social state supposes, then, a certain number and a certain order of crimes, these being merely the necessary consequences of its organisation’.

Additional information

Funding

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.