In recent years, many test instruments have been developed to assess the professional vision of (preservice) teachers. These instruments entail significant differences. They vary in the terminology used for the construct itself as well as in the assumed underlying dimensionality of a given test. Regarding methodological aspects, most tests use short realistic video clips as item stimuli, but task formats range from standardised tasks or rating items to open responses and written texts. Meanwhile, some studies have revealed only a low-to-moderate correlation between different task formats, which indicates low convergent validity. Finally, although construct validity has been commonly examined, information on the predictive validity of such tests remains limited. This chapter first provides an overview of characteristics and validation steps of existing video-based instruments. Then, it addresses the convergent and predictive validity of different task formats using its own data. In a correlational study, 85 preservice teachers worked on three different task formats measuring the professional vision of classroom management. They then taught a lesson in an internship, which students evaluated in terms of classroom management. Multilevel analyses indicated correlations with classroom management quality only for one task format. The chapter concludes with a critical review of the results and their implications.