Impacts daily team now consists of seven passionate people who work on projects in various composition:


Janine Plaisier graduated in social psychology and clinical psychology, both at the University of Amsterdam. Janine specialized in behavioral change in people, and effectivity of interventions. Her work has always included a combination of (international) research and policy. She has worked for the University of Amsterdam, the University of Dunedin, the the Dutch Ministry of Security and Justice and the Scientific Research Centre of the latter. In 2006 she founded Impact R&D. Since then, she managed many research and development projects. Also she presides expert meetings about a great variety of subjects, on a regular basis. She knows the procedures of the judicial partners well. In addition to her work for Impact R&D, Janine is a member of the Board of Criminal Justice and Youth Protection since 2014.


Jenneke van Ditzhuijzen is a psychologist and graduated cum laude in psychonomics. She is a researcher at heart. Additionally, she has experience as a social therapist in forensic psychiatric institutions. She has also worked for Correlation, an organization focused on international cooperation between organizations for social inclusion and health, with drug users and sex workers. Jenneke has since the start of Impact R&D collaborated in 2006 on numerous research projects and is also working on a PhD at the University of Utrecht.


Ischa van Straaten is a social psychologist and received his PhD in 2008 at the Radboud University in Nijmegen in the field of interpersonal relationships. After his PhD graduation, he took part in the National Think Tank, where he analysed (unhealthy) lifestyles among youth and developed an intervention for parental support. He then began to specialize in applied (policy) research, ministries, municipalities and executive organisations. He conducted both quantitative and quantitative research about a diversity of themes, such as poverty, digital services, child abuse, identity fraud and reintegration. For Impact R&D, Ischa focuses on evaluations and effect research, including research on the behaviour-influencing measure and the evaluation of the training “Kies voor Verandering” for adult detainees who want to change their lives.


Vera Hoetjes is a psychologist and has a MSc degree in clinical psychology at the University of Amsterdam. She collaborated on several projects for Impact R&D, such as aftercare for juvenile detainees, the training “Kies voor Verandering” for adult detainees who want to change their lives, treatment of offenders in the Penitentiary Psychiatric Centres of Dutch Prisons (PPCs) and developing a mission and vision of a forensic clinic for offenders with mental health and addiction problems. She is also involved in developing and testing a new method for e-supervision for offenders in the Dutch juvenile probation. She has not only theoretical knowledge on offenders but also practical experience as a psychological trainee therapist of offenders in an outreaching treament team in Amsterdam and of adolescents with psychosis at the Academic Medical Centre in Amsterdam.


Helly Pollaert studied sociology at the Erasmus University in Rotterdam. She is experienced in project evaluations, case studies and interviews with (former) detainees and penitentiary staff at Dutch Penitentiary Institutions, including the Penitentiary Institution in Roermond. For the Dutch Research Centre for Crime and Law she interviewed former detainees. For Impact R&D she worked, among other projects, on the evaluation of the training “Kies voor Verandering” for adult detainees who want to change their lives, the file study of the Behavior-influencing Measure and e-guidance.



Martine Knijnenberg graduated cum laude in criminology at the Vrije Universiteit in Amsterdam. She studied the development of loitering to juvenile offending and the criminogenic factors that play a role in this development. For Impact R&D Martine is involved in the file study of the Behavior-influencing Measure.


Danielle Bouma received her Bachelors in Interdisciplinary Social Sciences at Utrecht University and her Research Masters in Clinical Psychology at the University of Amsterdam. She has wide experience in methodology and also has experience as a psychological therapist and researcher at Jellinek Curative Addiction Treatment. Impact of R&D, she worked on several projects, such as literature research for the evaluation of training “Kies voor Verandering” for adult detainees who want to change their lives and the description of an innovative pilot project in a penitentiary institution.


Also former employees of Impact R & D sometimes still work with us:


Daphne Wiersema graduated cum laude as a social psychologist and she recieved her PhD in 2009 at the University of Amsterdam in a study of the way people interact with information that conflicts with important personal conviction. Daphne is a teacher and educational developer at the department of Training Applied Psychology of the Amsterdam University of Applied Sciences, and is an editor for the interdisciplinary Journal of Social Sciences. For Impact R&D she participated in an evaluation of aggression training in secondary schools, literature study on the relationship between money management and criminal behavior and research on “ZSM-youth” and health care for prisoners with psychiatric disorders.


Mayke Mol has a background of clinical developmental psychology. She is experienced in doing research with children in primary schools. As an assistant health care psychologist, she also provided counseling, intakes and diagnostics for Ergoselect, a practice for children and adults with learning and behavioral problems in Amsterdam. She is not only well versed in statistical methods and all the latest advances in the field of ICT, but also very experienced in performing thorough international literuurstudies, including domestic violence, resilience, juvenile crime, juvenile groups, and prisoners with mental health problems. Mayke is now a PhD candidate at Amsterdams Vrije Universiteit and InGeest mental health institute. Impact still works together with Mayke on e-supervision.