Torbjørn Skardhamar

• Allvin, Annica & Skardhamar, Torbjørn (2026). Stably Unstable? – Testing the Temporal Stability of Spatial Crime Patterns | Journal of Quantitative Criminology | Springer Nature Link. Journal of quantitative criminology. ISSN 0748-4518. doi: 10.1007/s10940-026-09691-5. Full text in Research Archive Show summary

  Criminological research has long suggested that microgeographical crime patterns are remarkably stable over time; however, there is little consensus on how stability should be defined or measured. This study investigates the stability of spatial crime patterns in Oslo, Norway, over two decades. We review definitions and operationalizations of spatial stability and test three central hypotheses. Using 20 years of police-registered crime data, we apply K-means longitudinal clustering to examine crime trends at a 100 × 100 m grid-cell level. We expand upon prior research by explicitly analysing within-cluster variation, conducting separate analyses by crime type, and testing robustness to changes in temporal resolution. We also demonstrate an alternative method using predefined criteria and compare the results. Although cluster-averages or -medians suggest spatial stability, we observe substantial variation within all clusters, suggesting places are easily interpreted to be more stable than they are. Whether most places exhibit low and stable crime trends, or whether chronic hot spots exist in Oslo, depends on the operationalization of stability. The degree of within-cluster variation casts doubts on whether conventional clustering approaches alone provide convincing evidence of persistent patterns, without closer scrutiny. Spatial stability may be overstated when inferred from cluster models relying on annual data. These crime patterns in Oslo are better understood as stably unstable, reflecting patterned variability rather than fixed persistence. Substantial local variation complicates interpretations of long-term stability. We argue for more careful operationalizations of spatial stability, closer attention to within-cluster variation, and greater consideration of temporary hot spots.

• Skardhamar, Torbjørn (2026). Black Ships: What Kind of Martial Art Is Sociology? Theory and society. ISSN 0304-2421. 55. doi: 10.1007/s11186-026-09744-5. Full text in Research Archive Show summary

  Pierre Bourdieu described sociology as a martial art but never specified what kind. The kind matters. The Japanese martial tradition offers a typology he did not draw: -jutsu, oriented toward defeating a real opponent; -do as competition, oriented toward internal scoring within a closed tournament; and -do as formation, oriented toward cultivating the practitioner rather than testing any claim against reality. I use this typology as a diagnostic framework. Sociology is predominantly -do. The costs are visible and cumulative, and they follow a pattern of slow response to external challenges: the credibility revolution, open science, and now AI. Open science and AI reshape what counts as rigorous work across methods, quantitative and qualitative alike. In 1853, Commodore Perry’s Black Ships arrived at Edo Bay, and the Shogunate discovered that two centuries of internal competition had not prepared it for an external force indifferent to its rules. The political order it had sustained did not survive the encounter. Sociology faces a comparable moment. I argue for a -jutsu imperative: not for any particular method, but for pressure-testing by standards the discipline does not control — a standard sociology has already committed to by claiming to produce knowledge about the social world, whether it acknowledges this or not.

• Jukka, Savolainen, & Skardhamar, Torbjørn (2026). The growth of knowledge in criminology: toward a more optimistic appraisal of theoretical progress. Theory and society. ISSN 0304-2421. 55. doi: 10.1007/s11186-026-09740-9. Full text in Research Archive Show summary

  Criminology is often portrayed as theoretically stagnant – a view reinforced by an influential review that interpreted the modest explanatory power of published research as evidence that criminological theory had failed to advance. We argue that this diagnosis rests on the wrong yardstick. Explained variance is neither a necessary nor a sufficient indicator of theoretical progress. Drawing on a post-Popperian conception of scientific growth emphasizing the problem-solving capacity of competing research traditions, we propose evaluating criminological theory according to its ability to resolve empirical puzzles and reduce crime-related harm. We illustrate this approach with two examples. First, evidence from competing theories of desistance has increasingly converged on the view that structural turning points are better understood as facilitators and consequences of change than as exogenous catalysts, shifting attention toward agency, cognitive transformation, and reciprocal processes. Second, routine activities theory emerged in response to the puzzle of rising crime amid postwar prosperity and generated a highly productive research tradition encompassing environmental criminology, hot-spots research, and situational crime prevention. In turn, situational crime prevention translated these theoretical insights into a cumulative body of evidence demonstrating the effectiveness of opportunity-reducing interventions. These episodes suggest that theoretical progress in criminology is best understood in terms of the capacity of competing research traditions to resolve anomalies, generate fruitful lines of inquiry, and produce practical solutions. More broadly, they demonstrate that theoretically pluralistic social sciences are capable of cumulative progress even in the absence of a dominant paradigm.

• Skardhamar, Torbjørn (2026). Query Authorship: A Framework for Systematic AIUse in Social Science. SocArXiv. Full text in Research Archive
• 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).

• Skardhamar, Torbjørn (2026). Standards in sociology: Agreeing on principles, disagreeing on ambition. Rationality and Society. ISSN 1043-4631. 38(3), p. 442–445. doi: 10.1177/10434631261464480. Full text in Research Archive Show summary

  Aksoy, Manzo, Birkelund, and Raub have written a thoughtful and well-argued position statement. I agree with most of what they say. My comment is not, therefore, primarily a disagreement but a question about actionable consequences. The three principles they advance — integration of theory and empirics, open science, and engagement with societal debates — are defensible. The problem is what the statement does with them. At each point where the argument reaches an operational conclusion, the language is strong — institutions “must establish” the conditions necessary to sustain open science, the community “should demand” sociology to be open — but the content of the demand is left unspecified. This is a statement that agrees with its own principles but declines to press them.

• 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.

• Svendsen, Vegard Testad; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn; Havnes, Ingrid Amalia & Bukten, Anne (2025). Substance use disorders, severe mental illness and risk of reoffending among women released from prison: a national cohort study. Scientific Reports. 15(1). doi: 10.1038/s41598-025-00215-y. Full text in Research Archive Show summary

  Women with a clinical history of a severe mental illness (SMI) or multiple mental disorders involving substance use disorder (SUD) might be at increased risk of re-offending after release from prison. This retrospective cohort study merged data from the Norwegian prison release study (nPRIS) with other registry sources. All women released from a Norwegian prison between 2011–2019 were followed for two years after date of release. Adjusting for several known risk factors, we used logistic regression to estimate risk of violent (VR), drug-related (DR) or other reoffending (ORE) after release among women with a history of SUD and severe mental illness (SUD-SMI), SMI, SUD and other mental illness (SUD-OMI) or a history of multiple SUDs (POLY-SUD) in comparison to a reference population with no history of such disorders or combination of disorders. Relative to the reference population, after adjusting for other relevant risk factors, women with a history of SUD-SMI (OR VR 2.27, 95% CI 1.37–3.76; OR DR 2.10, 95% CI 1.49–2.95), SUD-OMI (OR VR 1.81, 95% CI 1.11–2.47; OR DR 1.53, 95% CI 1.11–2.10) or POLY-SUD (OR VR 1.87, 95% CI 1.04–3.31; OR DR 2.51, 95% CI 1.80–3.49) were at significantly greater risk of violent and drug-related reoffending. Women with a history of SMI were at significantly greater risk of other reoffending (OR ORE 2.64, 95% CI 1.21–5.30). Women with a clinical history of a severe mental illness (SMI) or multiple mental disorders involving substance use disorder (SUD) have an elevated risk reoffending.

• Svendsen, Vegard Gjerden; Bukten, Anne; Skardhamar, Torbjørn & Stavseth, Marianne Riksheim (2024). Mortality in women with a history of incarceration in Norway: a 20-year national cohort study. International Journal of Epidemiology. ISSN 0300-5771. 53(2). doi: 10.1093/ije/dyae032. Full text in Research Archive Show summary

  Background Women carry a substantial burden of psychiatric, somatic and lifestyle-related morbidity in the prison context. By describing causes of death and estimating the risk and burden of mortality compared with the general population, this study investigates how mortality operates in this highly marginalized and under-researched population. Methods In this registry-based study of all women incarcerated in Norwegian prisons from 2000 to 2019 (N = 11 313), we calculated crude mortality rates, years of lost life and, by using mortality in age-matched women from the general population as a reference, age-standardized mortality ratios and years of lost life rates. Results Over a mean follow-up time of 10.7 years, at a median age of 50 years, 9% of the population had died (n = 1005). Most deaths (80%) were premature deaths from an avoidable cause. Drug-induced causes and deaths from major non-communicable diseases (NCDs) were most frequent (both 32%). Compared with women in the general population, women with a history of incarceration were more likely to die from any cause. Trends in annual age-standardized years of lost life rates suggest that the mortality burden associated with major NCDs has gradually replaced drug-induced causes. Conclusions Women with a history of incarceration die at a greater rate than their peers and largely from avoidable causes. The profile of causes contributing to the substantial burden of mortality placed on this population has changed over time and has important implications for future efforts to reduce morbidity and the risk of premature death following release from prison.

• 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
• Skjærvø, Ingeborg; Stavseth, Marianne Riksheim; Friestad, Christine; Skardhamar, Torbjørn; Tverborgvik, Torill & Bukten, Anne (2024). Characteristics and risk of reimprisonment among children and young adults in Norwegian prisons. A 20-year cohort study. Journal of criminal justice. ISSN 0047-2352. 93, p. 1–9. doi: 10.1016/j.jcrimjus.2024.102219. Full text in Research Archive Show summary

  Background Children, adolescents and young adults are in developmentally sensitive stages and can be disproportionally negatively impacted by imprisonment, yet these age groups are rarely described. Methods Complete records of all persons aged 15–34 imprisoned in Norway in the period 2000–2019 (n = 52,588) were linked with data from sociodemographic and police registries. Results Imprisoned children and adolescents were characterized by several markers for socioeconomic disadvantage, convictions for serious crime, and high rates of reimprisonment. Over the last 20 years, the number of children and adolescents in Norwegian prisons has declined, while their criminal profiles become increasingly severe. Conclusion Children and adolescents are characterized by an accumulation of sociodemographic and family-related risk factors and have an increased risk of reimprisonment even when controlling for a number of relevant factors. Preventative measures both in the community and in prison must be aimed at children and adolescents at risk.

• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2023). Psychiatric morbidity among women in Norwegian prisons, 2010-2019: a register-based study. BMC Psychiatry. 23(1). doi: 10.1186/s12888-023-04886-7. Full text in Research Archive Show summary

  Purpose Research suggests that women in prison have more mental health problems than men and are prone to suffer from more severe psychiatric disorders. This study utilizes national registry data to describe demographic and psychiatric gender differences in Norwegian prisons, and to investigate comorbid psychiatric disorders and time trends in psychiatric morbidity among women. Methods Longitudinal data from the Norwegian Prison Release Study linked with the Norwegian Patient Registry and data from Statistics Norway provided information on health care utilization, socioeconomic status, and history of psychiatric disorders among all individuals (nwomen = 5,429; nmen = 45,432) who were incarcerated in a Norwegian prison between 2010 and 2019. Results Women were more likely than men to have a history of any psychiatric disorder (75% vs. 59%). Substance use disorders and dual disorders were highly prevalent in both genders, yet highest among women (56 and 38% respectively, versus 43 and 24% among men). From 2010 to 2019, we found a considerable increase in the 12-month prevalence of most diagnostic categories among women entering prison. Conclusion Psychiatric and dual disorders are highly prevalent in Norwegian prisons, and especially among women. The proportion of women entering prison with a recent history of mental health problems has increased rapidly over the last decade. Women’s prison institutions need to adjust health and social services, and awareness about substance use and other psychiatric disorders in order to meet the increasing proportion of women facing these challenges.

• Tesli, Natalia; Jaholkowski, Piotr Pawel; Jaholkowski, Piotr Pawel; Haukvik, Unn Kristin Hansen; Jangmo, Andreas & Haram, Marit [Show all 16 contributors for this article] (2023). Conduct disorder - a comprehensive exploration of comorbidity patterns, genetic and environmental risk factors. Psychiatry Research. ISSN 0165-1781. 331, p. 1–10. doi: 10.1016/j.psychres.2023.115628. Full text in Research Archive
• Tesli, Martin Steen; Nesvåg, Ragnar; Haukvik, Unn Kristin Hansen; Gustavson, Kristin; Tesli, Natalia & Friestad, Christine [Show all 12 contributors for this article] (2023). Common genetic and environmental risk for personality disorders and psychotic-like experiences in young adult twins. Acta Psychiatrica Scandinavica. ISSN 0001-690X. 148(6), p. 561–569. doi: 10.1111/acps.13596. Full text in Research Archive Show summary

  Abstract Introduction Psychotic‐like experiences (PLE) have been associated with the subsequent emergence of psychotic disorders as well as several other domains of psychopathology. In this twin study, we estimated the genetic and environmental correlations between PLE and 10 personality disorders (PD). Methods Diagnoses of 10 PDs according to the Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) and PLE from the Composite International Diagnostic Interview (CIDI) were retrieved for 2793 young adult twins from the Norwegian Twin Registry. Risk for having a PD and PLEs was modeled using item response theory. Biometric twin models were fitted to estimate the genetic and environmental correlations between PDs and PLEs. Co‐twin control analysis was performed to estimate additional within‐family risk for PLEs when having a PD. Results Phenotypic overlap between PDs and PLEs ranged from 14% to 44% in males and from 11% to 39% in females, with the highest overlap for borderline PD in both sexes. In general, we found higher genetic correlations ( r  = 0.14–0.72) than environmental correlations ( r  = 0.06–0.28) between PDs and PLEs. The highest genetic correlations between PLE and PDs were found for borderline ( r  = 0.72), paranoid ( r  = 0.56), schizotypal ( r  = 0.56) and antisocial PD (r = 0.49). Conclusion We found that the co‐occurrence between PDs and PLE is the best explained by shared genetic determinants, with minor contributions from environmental factors. Interestingly, borderline PD was highly genetically correlated with PLE, warranting molecular genetic studies of this association.

• 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.

• Hart, Rannveig Kaldager; Pedersen, Willy & Skardhamar, Torbjørn (2022). Blowing in the wind? Testing the effect of weather on the spatial distribution of crime using Generalized Additive Models. Crime Science. 11(1). doi: 10.1186/s40163-022-00171-2. Full text in Research Archive Show summary

  Oslo, the capital of Norway, is situated in a North European cool climate zone. We investigate the effect of weather on the overall level of crime in the city, as well as the impact of different aspects of weather (temperature, wind speed, precipitation) on the spatial distribution of crime, net of both total level of crime, time of day and seasonality. Geocoded locations of criminal offences were combined with data on temperature, wind speed, and precipitation. Generalized Additive Models (GAMs) allowed us to map level of and the spatial distribution of crime, and how it was impacted by weather, in a more robust manner than in previous studies. There was slightly more crime in pleasurable weather (i.e. low precipitation and wind speed and high temperatures). However, neither temperature, precipitation nor wind speed impacted the spatial distribution of crime in the city.

• 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.

• Andersen, Synøve Nygaard; Holmboe, Morten & Skardhamar, Torbjørn (2021). Fører endringer i loven til endringer i rettspraksis?: En empirisk analyse av straffutmåling i voldsdommer etter en endring av den norske straffeloven. Nordisk Tidsskrift for Kriminalvidenskab. ISSN 0029-1528. 108(1), p. 8–26. doi: 10.7146/ntfk.v108i1.125561. Full text in Research Archive
• Sandbukt, Ingeborg Jenssen; Skardhamar, Torbjørn; Kristoffersen, Ragnar & Friestad, Christine (2020). Testing the static-99R as a global screen for risk of sex crime recidivism in a Norwegian routine sample. Sexual Abuse. ISSN 1079-0632. p. 1–18. doi: 10.1177/1079063220951194. Full text in Research Archive Show summary

  The Static-99R has been recommended for use as a first global screen for sorting out sex-convicted persons who are in need of further risk assessment. This study investigated the Static-99R’s predictive validity based on a nonselected Norwegian sample (n = 858) of persons released from prison after having served a sex crime sentence. After a mean observation period of 2,183 days, 3.4% (n = 29) had recidivated to a new sex offense. A higher number of recidivists were found among those with higher Static-99R total scores. The predictive contribution from each of the ten Static-99R risk items was investigated using standard logistic regression, proportional hazard regression, and random forest classification algorithm. The overall results indicate that the Static-99R is relevant as a risk screen in a Norwegian context, providing similar results concerning predictive accuracy as previous studies.

• Rege, Mari; Skardhamar, Torbjørn; Telle, Kjetil Elias & Votruba, Mark E (2019). Job displacement and crime: Evidence from Norwegian register data. Labour Economics. ISSN 0927-5371. 61(December 2019). doi: 10.1016/j.labeco.2019.101761. Full text in Research Archive Show summary

  We estimate the job displacement effect on criminal behavior for young adult Norwegian men separated from their plant of employment during a mass layoff. Displaced workers experience a 20 percent increase in criminal charge rates in the year of displacement, with effects declining thereafter. Effects are particularly large for property crimes, consistent with the idea that displaced workers turn to acquisitive crimes to replace lost earnings. However, effects are also sizable for violent and alcohol/drug-related crimes, indicating other mechanisms at work. We find strong evidence that displacement increases crime effects through the increased availability of time, and supportive evidence that psychological factors (mental distress, self-control) also play a role.

• Savolainen, Jukka; Aaltonen, Mikko & Skardhamar, Torbjørn (2018). Employment, Crime, and the Life Course. In Farrington, David P.; Kazemian, Lila & Piquero, Alex R. (Ed.), The Oxford Handbook of Developmental and Life-Course Criminology. Oxford University Press. ISSN 9780190201371. doi: 10.1093/oxfordhb/9780190201371.013.24. Full text in Research Archive Show summary

  This chapter focuses on life-course studies of employment and crime. It draws predominantly on quantitative results, but evidence from qualitative life-course studies are discussed as well. The purpose here is to provide an informed assessment of state-of-the-art scholarship. This chapter reviews studies that examine the capacity of employment (job entries) to curb criminal involvement. There are strong theoretical reasons to expect transitions to stable employment to contribute to the desistance process. Hence, the chapter explores the life-course studies of unemployment effects on criminal behavior (job exits). It concludes with a summary of the evidence and discusses implications for the next generation of studies on employment and crime.

• Geest, Victor van der; Verbruggen, Janna & Skardhamar, Torbjørn (2017). Changes in offending around official labor market entry: Vulnerable youths in transition to adulthood. In Blokland, Arjan & Geest, Victor van der (Ed.), The Routledge International Handbook of Life-Course Criminology. Routledge. ISSN 9781138813663. doi: 10.4324/9781315747996-14. Full text in Research Archive
• Gelman, Andrew; Skardhamar, Torbjørn & Aaltonen, Mikko (2017). Type M Error Might Explain Weisburd’s Paradox. Journal of quantitative criminology. ISSN 0748-4518. p. 1–10. doi: 10.1007/s10940-017-9374-5. Full text in Research Archive Show summary

  Simple calculations seem to show that larger studies should have higher statistical power, but empirical meta-analyses of published work in criminology have found zero or weak correlations between sample size and estimated statistical power. This is “Weisburd’s paradox” and has been attributed by Weisburd et al. (in Crime Justice 17:337–379, 1993) to a difficulty in maintaining quality control as studies get larger, and attributed by Nelson et al. (in J Exp Criminol 11:141–163, 2015) to a negative correlation between sample sizes and the underlying sizes of the effects being measured. We argue against the necessity of both these explanations, instead suggesting that the apparent Weisburd paradox might be explainable as an artifact of systematic overestimation inherent in post-hoc power calculations, a bias that is large with small N. © 2017 Springer Verlag

• Aaltonen, Mikko; Skardhamar, Torbjørn; Nilsson, Anders; Andersen, Lars H.; Bäckman, Olof & Estrada, Felipe [Show all 7 contributors for this article] (2016). Comparing employment trajectories before and after first imprisonment in four Nordic countries. British Journal of Criminology. ISSN 0007-0955. 57(4), p. 828–847. doi: 10.1093/bjc/azw026. Full text in Research Archive
• Skardhamar, Torbjørn & Savolainen, Jukka (2016). Timing of change: are life course transitions causes or consequences of desistance? In Shapland, Joanna; Farrall, Stephen & Bottoms, Anthony (Ed.), Global perspectives on desistance. Routledge. ISSN 9781138851009. p. 170–184. Full text in Research Archive
• Zoutewelle-Terovan, Mioara & Skardhamar, Torbjørn (2016). Timing of Change in Criminal Offending Around Entrance into Parenthood: Gender and Cross-Country Comparisons for At-Risk Individuals. Journal of quantitative criminology. ISSN 0748-4518. 32(4), p. 695–722. doi: 10.1007/s10940-015-9272-7. Full text in Research Archive
• Skardhamar, Torbjørn; Fekjær, Silje Bringsrud & Pedersen, Willy (2016). If it works there, will it work here?: The effect of a multi-component responsible beverage service (RBS) programme on violence in Oslo. Drug and Alcohol Dependence. ISSN 0376-8716. 169, p. 128–133. doi: 10.1016/j.drugalcdep.2016.10.019. Full text in Research Archive Show summary

  Background: The Stockholm Prevents Alcohol and Drug Problems (STAD) programme has been regarded as one of the most successful programmes to date, in reducing alcohol-related violence. This multicomponent Responsible Beverage Service (RBS) programme was implemented in Stockholm, Sweden, and has been documented to be extremely effective in reducing alcohol-related nightlife violence. The SALUTT programme in Oslo, Norway was carefully modelled on the STAD project. Aim: We investigate whether the results from STAD were replicated in the SALUTT intervention. Design: Using geocoded data, the level of violence in the intervention area was compared with different control areas before and after the intervention. Statistics: Autoregressive moving average models (ARIMA). Findings: The SALUTT programme had no statistically significant effect on violence. However, the level of violence in the different potential control areas of Oslo fluctuated without a clear common trend. Hence, it was difficult to establish proper control areas. Conclusions: The results from the Swedish STAD-intervention were not replicated in Oslo. Successful interventions are not necessarily replicated in other contexts, and the current literature does not shed sufficient light on the conditions under which such interventions actually work. Moreover, more attention should be devoted to the identification of adequate control areas in future research.

• Friestad, Christine & Skardhamar, Torbjørn (2016). The Criminal Career of Men Convicted of Rape: Evidence from a Norwegian National Cohort. Journal of Scandinavian Studies in Criminology and Crime Prevention. ISSN 1404-3858. 17(2), p. 150–165. doi: 10.1080/14043858.2016.1262595. Full text in Research Archive
• Skardhamar, Torbjørn (2016). Lovbrytere og lovbruddskarrierer. In Frønes, Ivar & Kjølsrød, Lise (Ed.), Det norske samfunn, bind 3. Gyldendal Akademisk. ISSN 9788205496927. p. 336–357. Full text in Research Archive
• Lyngstad, Torkild Hovde & Skardhamar, Torbjørn (2015). Family formation and crime: What role for the family network? Advances in Life Course Research. ISSN 1569-4909. doi: 10.1016/j.alcr.2015.09.007. Full text in Research Archive
• Skardhamar, Torbjørn; Savolainen, Jukka; Aase, Kjersti N. & Lyngstad, Torkild Hovde (2015). Does marriage reduce crime? Crime and justice. ISSN 0192-3234. 44, p. 385–446. doi: 10.1086/681557. Full text in Research Archive
• Andersen, Synøve Nygaard & Skardhamar, Torbjørn (2015). Pick a Number: Mapping Recidivism Measures and Their Consequences. Crime and delinquency. ISSN 0011-1287. doi: 10.1177/0011128715570629. Full text in Research Archive
• Skardhamar, Torbjørn; Monsbakken, Christian & Lyngstad, Torkild Hovde (2014). Crime and the transition to marriage: The role of the spouse’s criminal involvement. British Journal of Criminology. ISSN 0007-0955. 54(3), p. 411–427. doi: 10.1093/bjc/azu011. Full text in Research Archive
• Skardhamar, Torbjørn (2014). Lifetime conviction risk - a synthetic cohort approach. Journal of Scandinavian Studies in Criminology and Crime Prevention. ISSN 1404-3858. 15(1), p. 96–101. doi: 10.1080/14043858.2014.883175. Full text in Research Archive
• Skardhamar, Torbjørn; Aaltonen, Mikko & Leheti, Martti (2014). Immigrant Crime in Norway and Finland. Journal of Scandinavian Studies in Criminology and Crime Prevention. ISSN 1404-3858. 15(2), p. 107–127. doi: 10.1080/14043858.2014.926062. Full text in Research Archive
• Skardhamar, Torbjørn & Savolainen, Jukka (2014). Changes in Criminal Offending around the Time of Job Entry: A Study of Employment and Desistance. Criminology (Beverly Hills). ISSN 0011-1384. 52(2), p. 263–291. doi: 10.1111/1745-9125.12037. Full text in Research Archive
• Monsbakken, Christian; Lyngstad, Torkild Hovde & Skardhamar, Torbjørn (2013). Crime and the transition to parenthood: The role of sex and relationship context. British Journal of Criminology. ISSN 0007-0955. 53(1), p. 129–148. doi: 10.1093/bjc/azs052. Full text in Research Archive
• Lyngstad, Torkild Hovde & Skardhamar, Torbjørn (2013). Changes in Criminal Offending around the Time of Marriage. Journal of research in crime and delinquency. ISSN 0022-4278. 50(4), p. 608–615. doi: 10.1177/0022427812469516. Full text in Research Archive
• Skardhamar, Torbjørn & Skirbekk, Vegard (2013). Relative mortality among criminals in Norway and the relation to drug and alcohol related offences. PLOS ONE. 8(11). doi: 10.1371/journal.pone.0078893. Full text in Research Archive
• Skardhamar, Torbjørn & Telle, Kjetil Elias (2012). Post-release employment and recidivism in Norway. Journal of quantitative criminology. ISSN 0748-4518. 28(4), p. 629–649. doi: 10.1007/s10940-012-9166-x. Full text in Research Archive
• Lyngstad, Torkild Hovde & Skardhamar, Torbjørn (2011). Nordic register data and their untapped potential for criminological knowledge. Crime and justice. ISSN 0192-3234. 40, p. 613–645. doi: 10.1086/658881. Full text in Research Archive

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• Skardhamar, Torbjørn (2026). Sexual Offending and Criminal Careers: Evidence from Norwegian Register Data. Full text in Research Archive
• Skardhamar, Torbjørn (2026). Systematisk KI-bruk løser problemet med KI på eksamen. Full text in Research Archive Show summary

  Å formulere presise instruksjoner til KI, vurdere output kritisk og begrunne valgene man tar, er kognitivt krevende arbeid — ikke en snarvei utenom tenkningen. Systematikk og egne analytiske ferdigheter er ikke motsetninger. De er komplementære krav.

• 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). Hvordan bruke norske registerdata i kriminologisk forskning? Full text in Research Archive
• Skardhamar, Torbjørn (2025). Conducting surveys in a hard place. 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.

• Bukten, Anne; Stavseth, Marianne Riksheim; Tverborgvik, Torill; Clausen, Thomas; Lothe, Johan & Havnes, Ingrid Amalia [Show all 8 contributors for this article] (2024). Rus og psykisk helse. Full text in Research Archive
• Stavseth, Marianne Riksheim; Tverborgvik, Torill; Skardhamar, Torbjørn; Clausen, Thomas; Lothe, Johan & Havnes, Ingrid Amalia [Show all 8 contributors for this article] (2024). Rus og psykiske lidelser. 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
• Svendsen, Vegard Testad; Bukten, Anne; Stavseth, Marianne Riksheim & Skardhamar, Torbjørn (2024). WOMPRIS - Rus, helse og tilbakefall blant kvinner i norske fengsel. Full text in Research Archive
• Svendsen, Vegard Testad; Bukten, Anne; Stavseth, Marianne Riksheim & Skardhamar, Torbjørn (2024). Nederst ved bordet - Innsattes livskvalitet. Full text in Research Archive
• Sandberg, Sveinung; Marco, Martin Hernan Di; Goyes, David & Skardhamar, Torbjørn (2024). CRIMLA. Full text in Research Archive
• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2023). Mortality in women released from Norwegian prisons: A 20-year National Cohort Study. Full text in Research Archive
• Skardhamar, Torbjørn (2023). Criminal career trajectories vs developmental trajectories. Full text in Research Archive
• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2023). Psykiske lidelser blant kvinner i fengsel. Full text in Research Archive
• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2023). Psykiske lidelser og dødelighet blant kvinner i norske fengsel. 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
• Bukten, Anne; Lokdam, Nicoline; Skjærvø, Ingeborg; Ugelvik, Thomas; Skurtveit, Svetlana Ondrasova & Gabrhelík, Roman [Show all 20 contributors for this article] (2022). PriSUD-Nordic—Diagnosing and Treating Substance Use Disorders in the Prison Population: Protocol for a Mixed Methods Study. JMIR Research Protocols. 11(3). doi: 10.2196/35182. Full text in Research Archive Show summary

  Background: A large proportion of the prison population experiences substance use disorders (SUDs), which are associated with poor physical and mental health, social marginalization, and economic disadvantage. Despite the global situation characterized by the incarceration of large numbers of people with SUD and the health problems associated with SUD, people in prison are underrepresented in public health research. Objective: The overall objective of the PriSUD (Diagnosing and Treating Substance Use Disorders in Prison)-Nordic project is to develop new knowledge that will contribute to better mental and physical health, improved quality of life, and better life expectancies among people with SUD in prison. Methods: PriSUD-Nordic is based on a multidisciplinary mixed method approach, including the methodological perspectives of both quantitative and qualitative methods. The qualitative part includes ethnographic fieldwork and semistructured interviews. The quantitative part is a registry-based cohort study including national registry data from Norway, Denmark, and Sweden. The national prison cohorts will comprise approximately 500,000 individuals and include all people imprisoned in Norway, Sweden, and Demark during the period from 2000 to 2019. The project will investigate the prison population during three different time periods: before imprisonment, during imprisonment, and after release. Results: PriSUD-Nordic was funded by The Research Council of Norway in December 2019, and funding started in 2020. Data collection is ongoing and will be completed in the first quarter of 2022. Data will be analyzed in spring 2022 and the results will be disseminated in 2022-2023. The PriSUD-Nordic project has formal ethical approval related to all work packages. Conclusions: PriSUD-Nordic will be the first research project to investigate the epidemiology and the lived experiences of people with SUD in the Nordic prison population. Successful research in this field will have the potential to identify significant areas of benefit and will have important implications for ongoing policy related to interventions for SUD in the prison population.

• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2022). Rus og psykiske lidelser blant kvinner i fengsel. Full text in Research Archive
• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2022). Psychiatric morbidity in a ‘hardening’ prison population: Time trends and prevalence of psychiatric disorders among women in Norwegian prison, 2010 - 2019. Full text in Research Archive
• Svendsen, Vegard Gjerden; Stavseth, Marianne Riksheim; Skardhamar, Torbjørn & Bukten, Anne (2022). Kvinner (og kjønnsforskjeller) i fengsel. Full text in Research Archive
• Skardhamar, Torbjørn (2019). En fundamental misforståelse at Open Access ikke representerer kommersielle krefter. Full text in Research Archive
• Skardhamar, Torbjørn (2019). Spørsmålet er i hvilken grad systemet er rigget til å luke ut dårlig forskning. Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Skardhamar, Torbjørn (2019). Høringen om åpen tilgang til forskning var ingen utredning. Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Skardhamar, Torbjørn (2019). Ikke all Open Access er bra. Khrono.no. ISSN 1894-8995. Full text in Research Archive
• Andersen, Synøve Nygaard; Skardhamar, Torbjørn & Holmboe, Morten (2019). The effect of increased sentence length on recidivism and employment: A reform study of violent offenders sentenced to prison. Full text in Research Archive
• Skardhamar, Torbjørn (2019). Strict tests and forking paths. Full text in Research Archive
• Skardhamar, Torbjørn (2019). On the value of pre-registration and open science. Full text in Research Archive
• Skardhamar, Torbjørn (2019). Andrew Guthrie Ferguson: The Rise of Big Data Policing. Surveillance, Law and the Future of Policing. Norsk sosiologisk tidsskrift. 3(3), p. 228–230. doi: 10.18261/issn.2535-2512-2019-03-05. Full text in Research Archive
• Skardhamar, Torbjørn & Klemsdal, Lars (2019). Digitalisering – en introduksjon. Norsk sosiologisk tidsskrift. 3, p. 169–172. doi: 10.18261/issn.2535-2512-2019-03-01. Full text in Research Archive
• Skardhamar, Torbjørn; Lyngstad, Torkild Hovde & Berk, Richard (2018). Prediksjon av individers fremtidige kriminalitet. Full text in Research Archive
• Skardhamar, Torbjørn (2018). Hvordan forstå tilbakefall? Hva virker for å unngå nye lovbrudd? Full text in Research Archive
• Skardhamar, Torbjørn (2018). Examples of comparative studies: Experiences and review processes. Full text in Research Archive
• Lyngstad, Torkild Hovde; Rogne, Adrian Farner; Birkelund, Gunn Elisabeth; Hermansen, Are Skeie & Skardhamar, Torbjørn (2018). Ethnic Neighborhood Segregation and Residential Mobility Dynamics: Evidence from Norwegian administrative registers 1993-2013. Full text in Research Archive
• Pedersen, Willy; Skardhamar, Torbjørn & Fekjær, Silje Bringsrud (2017). Utelivsvolden og overskjenkingen i Oslo bare fortsetter. Full text in Research Archive
• Skardhamar, Torbjørn & Pedersen, Willy (2017). Har ikke lykkes med å redusere utelivsvolden i Oslo sentrum. [Journal]. Aftenposten. Full text in Research Archive
• Skardhamar, Torbjørn (2017). Lovbrytere. In Lomell, Heidi Mork & Skilbrei, May-Len (Ed.), Kriminologi. Universitetsforlaget. ISSN 9788215027067. Full text in Research Archive
• Skardhamar, Torbjørn (2017). Dagsnytt18. [Radio]. Dagsnytt18. Full text in Research Archive
• Skardhamar, Torbjørn; Hart, S.; Fekjær, Silje Bringsrud & Pedersen, Willy (2016). Changes in night-time economy and the concentration of violent events. Full text in Research Archive
• Skardhamar, Torbjørn (2016). Forbrytelsens matematikk. [Journal]. Dagens Næringsliv. Full text in Research Archive
• Skardhamar, Torbjørn (2016). This Guy Trains Computers to Find Future Criminals. [Journal]. BloombergTechnology. Full text in Research Archive
• Skardhamar, Torbjørn; Fekjær, Silje Bringsrud & Pedersen, Willy (2015). Effects of a multi-component responsible beverage programme service (RBS) on violent assaults in Oslo. Full text in Research Archive
• Skardhamar, Torbjørn (2014). Criminal trajectories: Taking stock and moving forward. The DLC criminologist. 2(1), p. 25–29. Full text in Research Archive
• Kaldager, Rannveig V & Skardhamar, Torbjørn (2013). Hva kan vi lære av umiddelbare effekter? Kommentar til Johnsen og Løken. Nytt Norsk Tidsskrift (NNT). ISSN 0800-336X. 30(4), p. 429–430. Full text in Research Archive
• Andersen, Synøve Nygaard & Skardhamar, Torbjørn (2013). Tilbakefall til gjentatt kriminalitet: Å måle gjentatt kriminalitet – hvem, hva og når? Samfunnsspeilet : Tidsskrift om levekår og livsstil. ISSN 0801-7603. p. 24–28. Full text in Research Archive Show summary

  Hvor høyt er tilbakefallet til kriminalitet i Norge? Tilbakefall blir målt på en rekke ulike måter og med svært forskjellige resultater. Tallene i vår undersøkelse varierer mellom 10 og 55 prosent, avhengig av hvordan gjengangerne blant lovbryterne er gruppert og analysert. Andelen som begår kriminalitet på ny er høyest i gruppen som er løslatt fra fengsel, sammenlignet med gruppene som er siktet eller dømt for begåtte forbrytelser.

• Pedersen, Willy & Skardhamar, Torbjørn (2011). QUESTIONABLE CONCLUSIONS ON CANNABIS AND CRIME Reply. Addiction. ISSN 0965-2140. 106(2), p. 450–451. Full text in Research Archive
• Skardhamar, Torbjørn; Thorsen, Lotte Rustad & Henriksen, Kristin (2011). Straffede innvandrere: Stor variasjon i innvandreres kriminalitet. Samfunnsspeilet : Tidsskrift om levekår og livsstil. ISSN 0801-7603. p. 49–53. Full text in Research Archive
• Jarland, Julie; Binningsbø, Helga Malmin; Lohne, Kjersti & Skardhamar, Torbjørn (2019). Courts of Conflict: The Impact of International Criminal Justice in Armed Conflict. Universitetet i Oslo. Full text in Research Archive
• Skardhamar, Torbjørn (2013). Straffegjennomføring med elektronisk kontroll i Norge. Konsekvenser for straffedes sysselsetting. Statistisk sentralbyrå (SSB). ISSN 9788253786254. Full text in Research Archive
• Skardhamar, Torbjørn (2013). Straffegjennomføring med samfunnsstraff i Norge. Konsekvenser for straffedes sysselsetting. Statistisk sentralbyrå (SSB). Full text in Research Archive
• Skardhamar, Torbjørn; Thorsen, Lotte Rustad & Henriksen, Kristin (2011). Kriminalitet og straff blant innvandrere og øvrig befolkning. Statistisk sentralbyrå (SSB). Full text in Research Archive

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