Teachers’ diagnostic competences are essential with respect to student achievement, classroom assessment, and instructional quality. Important components of diagnostic competences are teachers’ professional knowledge including content knowledge (CK), pedagogical knowledge (PK), and pedagogical content knowledge (PCK), their diagnostic activities as a specification of situation-specific skills, and diagnostic accuracy. Accuracy is determined by comparing a teacher’s observation of classroom incidents with subject-specific challenges to be identified from scripted instructional situations. To approximate diagnostic situations close to real-life, the assessment of science teachers’ diagnostic competences requires a situated context that was provided through videotaped classroom situations in this study. We investigated the relationship between professional knowledge (PCK, CK, PK) of 186 pre-service biology teachers, their diagnostic activities, and diagnostic accuracy measured with the video-based assessment tool DiKoBi Assess. Results of path analyses utilizing Rasch measures showed that both PCK and PK were statistically significantly related to pre-service teachers’ diagnostic activities. Additionally, biology teachers’ PCK was positively related to diagnostic accuracy. Considering higher effect sizes of PCK compared to PK, the findings support previous findings indicating the importance of PCK, thus demonstrating its importance in the context of subject-specific diagnosis as well.

A key challenge for teachers is the evaluation of teaching and learning situations in the classroom. Video-based instruments are considered as effective tools for measuring teachers’ skills for evaluating classroom situations. This article reports the development and validation of a video-based assessment tool for measuring biology teachers’ professional vision. Analyses of interviews using think-aloud protocols with in-service biology teachers showed that they perceived the staged videos in the video-based assessment tool as authentic. Furthermore, they identified biology-specific dimensions of instructional quality in the videos, and used aspects of professional vision while reasoning about the identified situations. Thus, results indicate the suitability of the video-based assessment tool for capturing professional vision with the potential to be used in further interventions within teacher education programs.

Diagnosing is an important aspect of teachers’ professional competence. To successfully diagnose classroom situations, one has to apply pedagogical content knowledge (PCK) in diagnostic activities (DA). Simulated classroom situations with embedded scaffolding can be an effective way of practising skills needed to foster diagnostic competences. In an intervention study with pre-post-test design using the video-based learning environment DiKoBi, we investigated the effects of scaffolds on the diagnostic competences of 57 pre-service biology-teachers in an early stage of university education. For the intervention, we developed two types of scaffolds: one providing additional PCK (PCK-scaffold) and one focusing on the diagnostic activities (DA-scaffold). Pre-service teachers were divided into four groups depending on the type of scaffold they received during the intervention (PCK-, PCK + DA-, DA- and control group). Pre-service teachers receiving PCK-scaffolds showed statistically significantly higher diagnostic competences in the post-test than in the pre-test. This includes the PCK- as well as the PCK + DA-group. For the other two groups, no significant improvement can be reported. Thus, we assume that the diagnostic competences of pre-service biology teachers can effectively be fostered by including PCK-scaffolds in DiKoBi and hence a minimum of PCK is necessary for successfully diagnosing in simulated classroom situations.

In a diagnostic context of reasoning about instructional quality, scientific reasoning skills can be described as diagnostic activities, which require professional knowledge. Different approaches to enhance pre-service teachers’ professional knowledge (PCK, CK, PK), as well as diagnostic activities exist. However, results about their effectiveness are still inconsistent. We systematically investigated the effectiveness of self-directed knowledge acquisition via texts on PCK, CK, PK, and diagnostic activities of 81 pre-service biology teachers following an experimental design. Paper-pencil tests, measuring PCK, CK, and PK, and the video-based assessment tool DiKoBi Assess, measuring diagnostic activities in the context of diagnosing instructional quality, were used pre and post an intervention. Intervention included four treatments on self-directed knowledge acquisition via texts on (1) PCK, (2) CK, (3) PK, (4) combination PCK/CK/PK. Treatment (5) served as control. Mixed ANOVAs showed large time effects for PCK and CK, but no interaction effect concerning knowledge facets between time and treatment for any of the treatments. Time effects might be due to pre-service teachers’ scientific reasoning on biology instruction that activated knowledge. An ANCOVA showed no significant effect of treatment on diagnostic activities either. We conclude that scientific reasoning about instructional quality is more effective for knowledge acquisition than text-work.