Criminal exposure in vulnerable areas

• Andresen, Anette Marie & Skardhamar, Torbjørn (2026). Rethinking Criminal Onset: Age at First Offence, Persistence, and Sex Differences. Journal of Developmental and Life-Course Criminology. ISSN 2199-4641. 12(1). doi: 10.1007/s40865-026-00315-x. Full text in Research Archive Show summary

  How frequent is criminal onset at each age, and to what extent does onset age predict continued offending across the life course for men and women? Criminological theory and empirical research put emphasis on young offenders, as early onset is a clear risk-factor for persistence, and often assume later onset implies lower risk of continued offending, yet the prevalence and persistence of adult onset remain disputed. It is also contentious whether there is any meaningful onset after reaching adulthood. While it is clear that the risk of onset declines with age, the dominant empirical approach in the literature is to identify the most common trajectory groups, using methods that are less likely to identify segments of unusual offending patterns, such as onset after normative ages. Using nationwide administrative records of solved offences for the resident population of Norway, we provide descriptive accounts of first registered offences in 2010 and subsequent continuation across all ages (N = 22 610; observation window 1982–2020). We find registered onset across all ages for both men and women, and while the risk of continuation declines with age, a non-ignorable number of offenders continue after onset even in older ages among both sexes (21% among men and 23% among women with onset at age 40 or older).

• Friestad, Christine & Skardhamar, Torbjørn (2025). Criminal Careers in the Making? Characteristics and Trajectories of Juveniles Charged With a Sexual Offense. Sexual Abuse. ISSN 1079-0632. doi: 10.1177/10790632251393988. Full text in Research Archive Show summary

  The present study investigates the onset, persistence and diversity in sexual offending by exploring Norwegian registry data on the social and criminal trajectories of juveniles charged with a sexual crime before the age of criminal responsibility, compared to juveniles charged with other types of offenses. The sample consisted of all persons aged 15 during the period 1997–2005 (N = 388,814). Of those, 19,559 juveniles (5%) were charged with a crime, mostly (83%) of a non-violent nature. For the remaining 16.9% (n = 3,309), the charge involved violence, either non-sexual (n = 2,991, 15.3% of those charged) or sexual (n = 318, 1.6% of those charged). Proportional hazard models were used to investigate background characteristics and risk of recidivism. Early onset of offending was related to a more disadvantaged background. Juveniles charged with violent and sexual offenses were generally younger and had more charges against them than juveniles charged with any other crimes. Early sexual crime carried higher hazard rate (HR) of future sexual crime (HR = 3.6) than early violent (HR = 1.9) and other crimes (HR = 1.4). The risk of later violent crime was similar among those with early onset violent (HR = 2.8) and sexual (HR = 2.5) crime, and higher than for early onset general crime (HR = 1.7). Since violent crime has a higher base rate than sexual crime, violence is more dominant in the criminal careers of people with early onset sexual offending. However, the majority of adult sexual criminal charges are raised against persons without a juvenile criminal record.

• Allvin, Annica; Gerell, Anders Emanuel Manne & Skardhamar, Torbjørn (2024). Vulnerable Areas in Oslo – Toward “Swedish Conditions”? Nordic Journal of Urban Studies. 4(2), p. 1–20. doi: 10.18261/njus.4.2.1. Full text in Research Archive Show summary

  In the past decade, Sweden has experienced a large increase in gang violence, strongly linked to what is termed “vulnerable areas.” This has sparked concerns about vulnerable areas across the Nordic countries. A recurring public debate is how to prevent the occurrence of “Swedish conditions” and their implications for gang violence, and, more broadly, ethnic segregation. As a result, there has been an increased emphasis on analyzing the spatial separation of different social groups and geographical crime patterns. The Danish government annually publishes a list of vulnerable neighborhoods; in 2022, the list included 17 neighborhoods. Similarly, the Swedish police release a biannual list of vulnerable areas, with the most recent edition containing 61 areas. There are differences in how vulnerable areas are defined and identified between and within these countries. Currently, Norway lacks a national strategy for identifying vulnerable areas, but the City of Oslo and the Oslo police department have recently adopted similar approaches. In this study, we use methods applied in Denmark (Danish Government, 2022a) and Sweden (Guldåker et al., 2021) to identify vulnerable areas in Norway. By doing so, we identify the differences that exist between the two methods. As discussions regarding vulnerable areas often revolve around crime prevention, we also analyze differences in crime levels among the identified areas within Oslo municipality. This will further build on our understanding about the relationship between crime and vulnerability. We discuss the inclusion of reported crime and ethnicity as predictors of vulnerable areas, and how this might lead to misdirected (criminal) policy measures. We observe there is lower residential segregation in Norway – while it does not suffer from Swedish (or Danish) conditions, other studies have shown an increase in urban segregation in Norway, and it remains important to prevent further increases to avoid negative development of social problems, including crime.

• Skardhamar, Torbjørn (2024). Lovbrytere. In Lomell, Heidi Mork & Skilbrei, May-Len (Ed.), Kriminologi. Universitetsforlaget. ISSN 9788215071992. Full text in Research Archive
• Skardhamar, Torbjørn (2022). Late bloomer offending patterns: Towards a harder empirical definition. Journal of Developmental and Life-Course Criminology. ISSN 2199-4641. p. 1–8. doi: 10.1007/s40865-022-00218-7. Full text in Research Archive Show summary

  Matsuda et al. (2022) show that late bloomers also exist in self-report data. They use a “dynamic” definition of late bloomer offending pattern as they have concerns with definitions based on arbitrary age cutoff points. But the approach does not make the groups less arbitrary than hard definitions. In this commentary, I argue that a hard definition has important advantages and demonstrates an alternative using a hard definition while exploring heterogeneity within the late onset group.

• Gerell, Anders Emanuel Manne; Allvin, Annica; Frith, Michael James & Skardhamar, Torbjørn (2022). COVID-19 restrictions, pub closures, and crime in Oslo, Norway. Nordic Journal of Criminology. ISSN 2578-983X. 23(2), p. 136–155. doi: 10.1080/2578983X.2022.2100966. Full text in Research Archive Show summary

  Alcohol consumption and crime are closely linked and there is often more crime near pubs and bars. Few studies have considered the impact of restricting access to pubs or bars on crime, and the present study aims to provide more insight into this by using the restrictions to combat the COVID-19 pandemic as a natural experiment. In Oslo, Norway, alcohol serving was banned twice during 2020, and at other times during the year, restrictions were placed on how late it could be served. In the present paper, these restrictions are analysed, alongside more general COVID-19 restrictions, to assess their association with crime. To identify these, we employ negative binomial regression models of daily crime counts for nine types of crime adjusted for the day of the week, the week of the year, and the year itself. This is in addition to the presence, or absence, of alcohol-related restrictions and more general COVID-19 restrictions. The findings suggest that both, general restrictions and bans on serving alcohol, reduced crime, although not universally across all crime types and times of the day. When pubs are ordered not to sell alcohol after midnight there appears to be an unexpected increase in crime.

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• Skardhamar, Torbjørn (2025). Utsatte områder i Norge? Full text in Research Archive
• Andresen, Anette Marie & Skardhamar, Torbjørn (2025). Crime throughout the life course: onset and continuation in offending. Full text in Research Archive
• Skardhamar, Torbjørn (2025). Machine learning and risk prediction of violence - theoretical considerations. Full text in Research Archive
• Skardhamar, Torbjørn (2025). Kriminologisk livsløpsperspektiv. Full text in Research Archive
• Skardhamar, Torbjørn (2025). Svenske tilstander_. Full text in Research Archive
• Andresen, Anette Marie & Skardhamar, Torbjørn (2025). Age of onset and continued offending. Full text in Research Archive Show summary

  This study aims to provide new evidence of age of onset and the amount of continued offending after onset at different ages. Early onset has been identified as a clear risk-factor for continued offending. Individuals with a later onset is associated with lesser risk for continued offending, but to what degree is uncertain. This uncertainty may be the result of a long standing discussion of whether late or adult onset exists at all. Defining late or adult onset has been proven difficult, where one reason may be the variety data used in the efforts to investigate the phenomenon. This study utilize total population data from Norway to investigate the existence of onset across all ages. We do so in an attempt to overcome some of the challenges in previous studies. The data include official offence data from 1992 to 2020. In this study we explore criminal onset among all full time Norwegian residents above the age of 10 with their first registered charge in 2010. The dataset also allows for descriptive information on continued offending after onset at different ages. The result confirm criminal onset is most common during late teens/early adolescence. Criminal onset, however, occurs in all ages, although less common with the increase in age. Similarly for continued offending, continued offending is most common among earlier onset, but there are instances of quite serious careers at later age of onset.

• Skardhamar, Torbjørn (2025). Life course trajectories vs vriminal career trajectories. Full text in Research Archive Show summary

  Individuals’ offending over time is often described using trajectory modeling, with offending considered as a function of age. This approach follows naturally from a developmental and life course perspective. Alternatively, offending trajectories can be described as a function of time since the onset of offending, thereby avoiding the modeling of criminal careers before any observed offending behavior has begun. In this paper, I demonstrate how these different approaches can lead to diverging results, and argue that chronological age is not always the most relevant time scale. This empirical analysis utilizes total population registry data from Norway.

• Frith, Michael James (2025). Age Matters: Using Age Windows to Measure Offending · CrimRxiv. doi: 10.21428/cb6ab371.d38781a0. Full text in Research Archive Show summary

  While long-term population register data in the Nordic countries offer unique opportunities for criminological research, systematically recorded and linkable crime data are often limited to more recent and shorter time periods. As such, criminological research, particularly intergenerational crime research, often rely on observing offending within relatively short age windows, for example, up to age 30, as a substitute or proxy for measuring longer-term offending. This study uses Norwegian population register and Police charges data to assess how offending measured at specific ages and within three-, five- and ten-year age windows corresponds to broader involvement in offending (between ages 15-42, 20-47, and 25-52). While offending at individual ages shows relatively weak correspondence to longer-term involvement in offending, Pearson correlations show that offending during the late twenties and early thirties, particularly the 10-year window covering ages 20–29, are strongly linearly related and can explain over 80% of variation in long-term offending totals. In contrast, the rank-order and prevalence of offending correspond less strongly but relate most closely at earlier ages (e.g., 15–24), however, these measures depend much more heavily on longer observation windows. The findings highlight both the utility and limitations of using age-limited observation windows in crime research.

• Frith, Michael James (2025). The Longitudinal Concentration of Offending Among Individuals and Families · CrimRxiv. doi: 10.21428/cb6ab371.bfac7b78. Full text in Research Archive Show summary

  Purpose: This study examines the extent to which offending is concentrated among individuals and families, how the concentration has changed over time, and to what degree the longitudinal concentration of offending is driven by the same individuals and families consistently offending at similar levels. Methods: We used linked national police and population register data from Norway covering 2004–2018 to analyze the offending behavior of over 5 million individuals and their nuclear, immediate, and extended families. Concentration was assessed using three Gini coefficients: the traditional, generalized, and Poisson-Gamma. To examine stability in offending intensity, we introduced consistency indices that measure the degree of consistency of offending levels over time. Results: Offending was highly concentrated with the top 0.1% of individuals committing 22% of all offences, and 5% accounting for 88%. For families, the top 5% were responsible for 55–73% of offences. Over time, crime became more concentrated at the population level but, among those who offended, more evenly distributed at lower levels. Consistency indices revealed that while most individuals and families consistently abstained from offending, the identities of higher-rate offenders often changed over time with few maintaining high levels of criminal activity across multiple years. Conclusions: While crime is heavily concentrated, the individuals and families responsible, particularly for high levels of crime, vary over time, with most offending occurring more often at lower and more uniform levels. This temporal instability and growing uniformity of offending levels poses challenges for designing effective, long-term interventions and allocating resources efficiently.

• Frith, Michael James (2024). How far does the apple fall? Offence type-similarity transmission between family members. Full text in Research Archive
• Gerell, Anders Emanuel Manne; Allvin, Annica; Skardhamar, Torbjørn & Andersen, Bengt (2024). Vi har ikke svenske tilstander i Norge. Full text in Research Archive
• Skardhamar, Torbjørn (2023). Criminal career trajectories vs developmental trajectories. Full text in Research Archive
• Frith, Michael James (2023). Pastures New? Assessing the impact of domestic migration on criminal careers in Norway. Full text in Research Archive
• Frith, Michael James (2023). To Me, To You! A Longitudinal Analysis of the Intra-familial Transmission of Crime. Full text in Research Archive
• Gerell, Anders Emanuel Manne (2022). Brottslighetens geografi, gängvåld och utsatta områden. Full text in Research Archive
• Gerell, Anders Emanuel Manne (2022). Utsatta områden och utsatta livsvillkor. Full text in Research Archive
• Gerell, Anders Emanuel Manne (2022). Utsatta områden, trygghet och tillit till politiet. Full text in Research Archive
• Skardhamar, Torbjørn (2022). Forecasting future criminal activity at birth. Full text in Research Archive
• Skardhamar, Torbjørn (2022). Kriminalitet, alder og lovbruddskarrierer. In Frønes, Ivar & Kjølsrød, Lise (Ed.), Det norske samfunn - Bind 3. Gyldendal Akademisk. ISSN 9788205572324. Full text in Research Archive
• Skardhamar, Torbjørn (2022). Neighbourhood risk factors of victimization. Full text in Research Archive
• Frith, Michael James (2022). Crime on street segments: A latent class trajectory analysis. Full text in Research Archive
• Frith, Michael James (2022). Migration and criminal career trajectories in Norway. Full text in Research Archive

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