Dekker, alongside Pieter Kubben and Michel Dumontier, co-authored Fundamentals of Clinical Data Science which delved into topics such as personalized medicine offering insights in a healthcare-optimized style without requiring mathematical or coding expertise. His research on the increasing significance of clinical decision-support systems in radiation oncology discussed the multistage process involved in developing robust prediction models, emphasizing the critical role of predictive models in optimizing treatment outcomes. In a collaborative study, he proposed a system for characterizing and classifying oligometastatic disease.