Digital technologies are increasingly used in assessment. On the one hand, this use offers opportunities for teachers to practice assessment more effectively, and on the other hand, it brings challenges to the design of pedagogically sound and responsible digital assessment. There is a lack of validated instruments and models that explain, assess and support teachers' critical pedagogical practice of digital assessment. This explorative work first develops and validates a survey instrument to examine teachers' digital assessment practices. Secondly, we build a model to investigate to what extent teachers' pedagogical digital assessment knowledge is a foundation for the future of digital assessment (i.e., authentic, accessible, automated, continuous and responsible). A total of 219 university teachers at a large European university participated in the survey study. Factor exploratory analysis and structural equation modelling were used to validate the reliability and validity of items and internal causal relations of factors. The results show the survey is a valid and reliable instrument for assessing teachers' digital assessment practice in higher education. Teachers' pedagogical knowledge and pedagogical content knowledge of digital assessment is critical, while teachers' technological pedagogical knowledge seems to have a more limited impact on the future of digital assessment.