Samenvatting

Montessori education has existed for over 100 years, with almost 16,000 schools worldwide. The results from research on Montessori effectiveness are difficult to interpret due to different ways of implementing the method. To elucidate research findings from future studies on Montessori education more adequately, it is necessary to develop and validate an instrument to measure implementation. This study describes the need to assess Montessori implementation to gain a better understanding of its effectiveness, the validation of the Dutch Teacher Questionnaire of Montessori Practice (TQMP), and explores the implementation of Montessori principles in Dutch Montessori schools. Results among 318 elementary Montessori teachers indicated a 5-factor model. Although the psychometric properties of this version seem promising, there is room for improvement, particularly in enhancing the reliability of the factors. Mean scores and the range of scores highlight considerable variation among the five factors in Montessori implementation, suggesting variation in the way Dutch schools apply these Montessori principles.