Yesterday, Tineke Rombout succesfully defended her Master of Education thesis. The theme of the thesis was Effective feedback. It is known that various forms of feedback can have significant effects on learning processes. But can teachers in elementary education provide effective feedback, especially if they are in the beginning of their career? Providing high-quality feedback is a complex teaching skill. This thesis shows these complexities, and calls for continuous professional development for teachers to develop this skill. Congratulations Tineke, and thank you Dr Joachim Wetterling for your role as supervisor of this thesis.