The aim of this study was to investigate the scale and network structure of prostitution in the northern provinces of the Netherlands. This study tries to answer three research questions – using a social network analysis – about (1) the size of the prostitution network, (2) the formation of subgroups, and (3) key positions within the networks. The findings show that approximately two thirds of the researched prostitution networks is still unregistered, while there are indications that the outcome of the estimate is in line with the actual situation. Furthermore, results show that prostitutes have a tendency to form subgroups on the basis of the same nationality, which indicates that homophily plays a role in the formation of subgroups. The identification of the actors who occupy key positions in the network were based on the key player problem (KPP). A striking finding was that organizers of prostitution (such as pimps) did not have a central position in the networks. These findings provide insight into the way in which prostitution is registered, and provide points of departure for interventions to disrupt the network or, on the contrary, to strengthen it.

In this study the authors examined a criminal youth gang of 35 persons in the Netherlands, using social network analysis, to answer the following questions. To what extent is it possible by means of police records to estimate the size of the complete social network of this criminal youth gang? To what extent are members of this original group part of the core of the complete network? To what extent have members of the original group a central position in the complete network (key players) and are, as such, responsible for holding the complete network together? Information is derived from police records. Results show that the size of the total network of this criminal youth gang consists of 593 individuals with a core of around hundred persons. Seven persons were identified as key players, among which six persons belonged to the original group. The social network approach in this study provides police and justice important indications for a more tailored approach regarding individuals within criminal networks.

Social network analysis (SNA) has taken its place in the field of criminology, although among Dutch criminologists the emphasis remains on conceptual contributions. Meanwhile, the world of criminal investigation and intelligence has witnessed the development of a blossoming SNA-practice. The emergence of big data makes SNA an indispensable tool to exploit the oceans of data in a meaningful way. Unfortunately, when it comes to employing SNA, academia and the investigations and intelligence domains remain separated. While Dutch analysts adopt scientific ideas and concepts, they rarely contribute to the body of literature; confidential SNA reports remain inaccessible. Shedding light on over forty SNA related internal police studies, this article bridges the gap between Dutch academic criminologists and ‘pracademics’ in law enforcement.

In hoeverre is de toegenomen aandacht voor ex-ante-evaluatie, zowel in beleidskringen als in publicaties, terug te zien in de evaluatiepraktijk? Op basis van de uitkomsten van een recente door het WODC verrichte metastudie gaan we in deze bijdrage in op aard en omvang van 306 in de periode 2005-2011 voor de rijksoverheid verrichte ex-anteanalyses. Daarbij besteden we ook aandacht aan hun voorspellingskracht. We onderscheiden acht typen ex-anteanalyses. Combinaties van studietypen, kosten-batenanalyses en verkennende ( quickscan) studies komen het meest voor. Van de bestudeerde analyses was 15% gevolgd door een latere evaluatie (ex durante of ex post). Redenen waarom latere evaluaties ontbreken, zijn dat het ex ante onderzochte beleid inmiddels van de baan is, of nog in de ontwerpfase verkeert. In sommige gevallen was het waarschijnlijk nog te vroeg voor evaluatie. Lang niet alle latere evaluaties sluiten aan op het ex-anteonderzoek. Wanneer dat wel het geval is, worden voorspellingen soms wel, soms deels en soms niet bevestigd. Aan het belang van zowel ex-ante- als ex-postonderzoek doen deze observaties niet af; bevindingen uit ex-postevaluaties over wat in het verleden of elders gewerkt heeft, zijn een onmisbare bron van kennis voor toekomstig ex-anteonderzoek en daarmee voor beleid en wetgeving.

In this study Forensic Social Network Analysis (FSNA) as an social intervention method on behaviour of forensic psychiatric patients on leave is described. It is assumed that FSNA takes effect through social control and social support of significant network members. Fifteen patients from Forensic Psychiatric Centre Dr. S. van Mesdag (The Netherlands) and over fifty of their significant others have been interviewed during this study. The results imply that during the rehabilitation-phase less incidents and violations of parole orders were caused by patients on which FSNA was applied. This supports the positive role of significant others of patients during the rehabilitation-phase and perhaps in forensic psychiatric supervision.

The first part of the article provides a review of the literature concerning the prevalence of people with learning disabilities in forensic settings, the treatment programs for this population, and the evidence for the effectiveness of these programs. In the second part, a large prospective study into the effectiveness of long-term inpatient treatment in a Dutch treatment center is reported. Preliminary results indicate that the percentage of improved patients in terms of reduction of criminogenic needs increases steadily, and that about half of the patients significantly improve within the first two years of the treatment. In addition, patients are released to settings which are less restrictive than the pre-treatment settings.

Increasingly, instruments for risk assessment have been used for the assessment of future violence. This article provides an overview of the risk assessment instruments that are used in the Netherlands for the prediction of criminal recidivism. The quality of these instruments is regarded by examining studies on the interrater reliability and the predictive validity. The benefits as well as the limitations of risk assessment instruments are discussed. It is concluded that these instruments can be valuable, especially for research on treatment effects in the field of forensic psychiatry. On the other hand, it has to be acknowledged that with risk assessment instruments, the possibility to predict criminal recidivism on individual level is still limited. Psychologist and psychiatrists, presenting a mental health assessment to the court, have to inform the judge correctly about these limitations.

Using data from judicial documentation on adult adjudicated offenders in the Netherlands, an actuarial risk prediction instrument has been developed. StatRec estimates the four year reconviction rate of adult offenders, based on a limited number of static factors. The metric qualities of the scale are good. StatRec produces a precise estimate of the base rate in the group of individuals with the same combination of background characteristics as the offender. The scale does not use dynamic and situational factors that may influence the risk of reoffending. Taking them into account only slightly enhances the predictive power. StatRec can be used to validate more specific risk assessment tools.