Our Publications

Cornelisz, I., Van der Velden, R., de Wolf, I. & Van Klaveren, C. (2019) “The Consequences of Academic Dismissal for Academic Success”. Studies in Higher Education. Published online March 30, 2019.


Academic dismissal policies are increasingly implemented to promote academic success, with existing empirical evidence mostly restricted to short-run outcomes. This study examines long-term academic outcomes of academic dismissal for two cohorts (N=1707) of first-year bachelor students in Economics and Business at a Dutch university. Using administrative records, regression discontinuity design estimates suggest that academic dismissal does not relate to a difference in the propensity of graduation, nor to a change in study delay, when comparing students around the academic dismissal threshold. Not meeting this credit-threshold forces students to leave, and most decide to re-enroll in the same (43.4%) program elsewhere or at least within the academic domain (41.9%). Thus, while academic dismissal forces students to switch, its intended purpose of redirecting students to a different field of study is not observed. Implications for why academic dismissal might not deliver on the intended efficiency or effectiveness gains are discussed.

Donker, T., Cornelisz, I., Van Klaveren, C., Van Straten, A., Carlbring, P., Cuijpers, P., & Van Gelder, J.L. (2019) “Effectiveness of Self-guided App-Based Virtual Reality Cognitive Behavior Therapy for Acrophobia: A Randomized Clinical Trial.”. JAMA Psychiatry. Published online March 20, 2019. 


Importance Globally, access to evidence-based psychological treatment is limited. Innovative self-help methods using smartphone applications and low-cost virtual reality have the potential to significantly improve the accessibility and scalability of psychological treatments.

Objective To examine the effectiveness of ZeroPhobia, a fully self-guided app-based virtual reality cognitive behavior therapy (VR CBT) using low-cost (cardboard) virtual reality goggles compared with a wait-list control group and to determine its user friendliness.

Design, Setting, and Participants In a single-blind randomized clinical trial, participants were enrolled between March 24 and September 28, 2017, and randomly assigned (1:1) by an independent researcher to either VR CBT app or a wait-list control group. A total of 193 individuals aged 18 to 65 years from the Dutch general population with acrophobia symptoms and access to an Android smartphone participated. The 6 animated modules of the VR-CBT app and gamified virtual reality environments were delivered over a 3-week period in participants’ natural environment. Assessments were completed at baseline, immediately after treatment, and at 3-month follow-up. Analysis began April 6, 2018, and was intention to treat.

Intervention Self-guided app-based VR CBT.

Main Outcomes and Measures The primary outcome measure was the Acrophobia Questionnaire. The hypothesis was formulated prior to data collection.

Results In total, 193 participants (129 women [66.84%]; mean [SD] age, 41.33 [13.64] years) were randomly assigned to intervention (n = 96) or a wait-list control group (n = 97). An intent-to-treat analysis showed a significant reduction of acrophobia symptoms at posttest at 3 months for the VR-CBT app compared with the controls (b = –26.73 [95% CI, −32.12 to −21.34]; P < .001; d = 1.14 [95% CI, 0.84 to 1.44]). The number needed to treat was 1.7. Sensitivity and robustness analysis confirmed these findings. Pretreatment attrition was 22 of 96 (23%) because of smartphone incompatibility. Of the 74 participants who started using the VR-CBT app, 57 (77%) completed the intervention fully.

Conclusions and Relevance A low-cost fully self-guided app-based virtual reality cognitive behavioral therapy with rudimentary virtual reality goggles can produce large acrophobia symptom reductions. To our knowledge, this study is the first to show that virtual reality acrophobia treatment can be done at home without the intervention of a therapist.

Trial Registration identifier: NTR6442

Van Halem, N., Van Klaveren, C. & Cornelisz, I. (2017). Oefent een leerling meer door niveaudifferentiatie? Het effect van data-gestuurde differentiatie op leerinspanning en de rol van eerder behaalde cijfers, Pedagogische Studiën, 94(3), 182-194.


While computer-based differentiation is increasingly common in education, no actual evidence on the effects on the learning process is established yet. This study investigates the effect of data-driven differentiation on students’ learning activity, and its relation with obtained summative grades. This study takes place over the course of one school year, in the context of the lower grades of secondary education and the courses biology, economics, and history. Students were randomly assigned to data-driven differentiation within an existing digital learning environment. Analyses were disaggregated into quartiles of students average achievement level and based on a longitudinal hierarchical regression model (N = 606), yielding the proportion of variance between and within students (over time). Results suggest that datadriven differentiation positively affects learning activity amongst certain – mostly high-achieving – students. Future research is required in order to fully explain these results and optimise datadriven differentiation in education.