“…One of the main hypotheses to explain these difficulties is that, although the videos in most teacher education programs are designed to encourage professional development, PTs are limited in their capacity to identify relevant classroom events by their actual level of professional development. Thus, according to many authors, PTs are unable to selectively attend to the most relevant events in the classroom video because they lack sufficient knowledge about the teaching profession and specific subject areas to identify these events (Hiebert, Gallimore, & Stigler, 2002;Sherin & van Es, 2005;Stürmer, K€ onings, & Seidel, 2014;van den Berg, 2001). The study of Blomberg et al (2011) presents a good example of how PTs' generic and subject-based knowledge, learned in methodological courses, plays a key role in the process of selective attention: when PTs lack the necessary knowledge, they simply fail to identify the most relevant events in the videos.…”