Key aspects of instructional quality, such as cognitive activation, constructive learning support, and successful implementations of formative assessment, are reflected in and become visible in interaction processes (e.g., Klieme, 2019; Meseth & Proske, 2011). The increasing interest of standardized classroom research in interaction processes and their quality is expressed, among other things, in a growing number of conceptualizations and survey instruments that capture components of interaction (e.g., Denn et al. 2016; Hamre et al. 2013; Molinari et al. 2012; Pfister et al. 2015; Ranger 2017; Van de Pol et al. 2010). The video study makes it possible not only to capture more generic features of instructional quality (classroom management, social interaction quality, and cognitive activation), but also to investigate subject didactic quality and subject aspects of classroom interaction. The video study does this in a systematizing and comparative manner by asking teachers to focus on challenging, cognitively activating tasks in both German and mathematics classes.

It is planned to survey German and mathematics lessons (twice 2 hours) in about 20-25 elementary school 3^rd grade classes. According to the class teacher principle in elementary school, the German and mathematics lessons should each be taught by the same teacher.

The content to be taught is specified in both subjects: The German lessons should be about spelling strategies and the mathematics lessons should be about ways of solving and discovering arithmetic patterns and structures. For plenary German lessons, so-called spelling conversations (Geist 2018; Leßmann 2014; Schröder 2014, among others) have considerable cognitive activation potential, if the teacher behaves appropriately, and can stimulate children to explicate, apply, and further develop their knowledge of strategies for spelling words (Hanisch 2018). For student work phases, tasks for error correction, self-explanation, and justification (Fay 2012) can challenge explicit problem-solving knowledge and make it visible in oral negotiations or materialize in writing. Therefore, these phases have a high potential for the observation of subject-specific learning.

In mathematics classes, mathematically rich, ‘naturally differentiating tasks’ enable the connection of self-construction and co-construction (Rathgeb-Schnierer & Rechtsteiner 2018). These kinds of tasks challenge students to independently engage with mathematical facts, allow for solution paths at different levels, and discussion on approaches and discoveries (e.g., Ruwisch 2003; Walther 2004). In addition, these tasks offer various possibilities for the cognitive activation of the students in work and exchange phases. In terms of content, the tasks refer to the exploration of arithmetic patterns and structures, since numerous relevant task formats are already established in teaching practice in this area (e.g., number houses, number walls, operatively structured task series), so that there are possibilities for connection.

In this way, topics are selected in both subjects that allow or suggest an in-depth examination of the subject matter and that allow for a significant variation in teaching approaches. In addition, both topics can be integrated relatively flexibly into the curriculum of the third school year, so that it is not necessary to deal with them in a fixed period of the school year. In both lessons, the teachers are asked to include a longer cooperative student work phase in addition to plenary instruction to comparatively examine the subject interaction in different social forms. The focus of the study is the relationship between the social-emotional and the subject-related interaction quality, which will be recorded independently by rating and coding procedures to be developed. The supportive behavior of the teachers, as well as the student-student interactions, will be considered. The data to be collected will make it possible to systematically examine relationships between generic and subject aspects of the quality of elementary school teaching.

The video recording of the lessons is supplemented in each class by various surveys, which are conducted over a period of four to six weeks as a way to reduce the burden on those involved. During this period, tests and questionnaires will be used to assess facets of teachers’ professional competence in both subjects. Methods for determining didactic knowledge are used that were developed by cooperation partners of the application consortium and can be modified, if necessary, in consultation with them (Knievel et al. 2015; Riegler & Wiprchtiger-Geppert 2016; Jeschke et al. 2020) In addition, subject-related self-assessments of the teachers, such as their own competence beliefs, will be collected with a questionnaire prior to the video study. These data will be used to examine the extent to which teachers’ instructional actions, and thus observable patterns of interaction and realized practices, can be predicted by the recorded competence levels. Finding suitable connections will be of considerable relevance for questions of lesson development and also have implications for teacher training.

In terms of timing of the videotaped lessons, student-specific learning levels will be assessed with the German Mathematics Test (DEMAT) or the PERLE Mathematics Test and the Hamburg Writing Sample (HSP) to examine how teachers interact with students at different levels of proficiency. Furthermore, teachers are asked to assess of students’ performance in spelling and arithmetic. A guided interview with the teachers is planned immediately after the lesson, in which they will be asked about their planning activities to determine the depth and differentiation of the lesson preparation. The aim is to investigate the extent to which the subject-specific quality of instruction, as well as certain generic dimensions of instructional quality, such as classroom management, are related to the level of instructional preparation.

Quantitative analyses focus, among others, on the social-emotional and on the subject-related quality of teaching and apply low-intensity coding methods and high-intensity ratings. With the help of Markov chains, for example, transition probabilities can be calculated and patterns of progression in interactions can be determined. In addition, the interrelationships between the quality dimensions will be analyzed to examine the extent to which the generic and subject-specific aspects of teaching are independent of each other. By capturing instruction in plenary and in the cooperative setting, the data set also allows us to answer research questions directed at the adaptivity of teachers’ support behaviors, or at the differential analysis of student behavior. For example, it is possible to examine the type of support teachers provide to lower- and higher-performing students and the extent to which lower-performing students request help and support more frequently. By observing students in cooperative work phases, the video material will be supplemented with data on mutual support, the distribution of roles in cooperative settings, and the professional and social quality of discussion among learners.

The video study will be technically implemented in such a way that both standardized and qualitative-reconstructive approaches will be possible. Criterial determinations and coding will be complemented by reconstructive analyses, and the arrangement of teaching derived from the research design can itself be made the object of study (Fankhauser 2013; Baltruschat 2018).