Professional Knowledge of Chemistry Teachers

Prof. Dr. Elke Sumfleth - Research Interests

 

Professional Knowledge of Chemistry Teachers

 

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Assessment of content knowledge and pedagogical content knowledge of chemistry teachers

In literature there is no consensus regarding the impact of single dimensions of professional knowledge, although an interaction between different dimensions is always described. Differences can be found concerning the number of dimensions as well as their emphases (Grossman, 1990; Shulman, 1987). Three aspects can be seen as common characteristics of all known definitions: content knowledge (CK), pedagogical content knowledge (PCK), and pedagogical knowledge (PK), whereas they are not listed as distinct dimensions in every definition or are named in different ways (Park & Oliver, 2008).

CK is understood as knowledge of subject-specific contents and methods. It is much more than the subject matter knowledge, which is learned by students, or even everyday knowledge based on academic grounding; rather, it is formed as a result of curricular working and structuring of subject-specific content for teaching (Baumert & Kunter, 2006).

PCK is the attribute which distinguishes between a content specialist and a teacher (Shulman, 1987). It is based on subject-specific knowledge about teaching and learning specific contents. "PCK [...] is constituted by what a teacher knows, what a teacher does, and the reasons for the teacher's actions" (Baxter & Lederman, 2006).

Finally, PK is knowledge about broad principles and strategies of classroom management, organization and learning strategies (Baumert & Kunter, 2006).

Existing studies using this trisection of teachers' professional knowledge (Baumert & Kunter, 2006) show correlations between CK and PCK which are specific for different school types (Krauss et al., 2006). School types were differentiated into intensified general education and non-intensified general education. Intensified general education is the secondary education phase whose successful completion leads to acquisition of the higher education entrance qualification (Bonsen, Bos, & Frey, 2008). For teachers of this school type, a higher correlation (r = .96) between CK and PCK is found than for teachers, who do not work on intensified general education levels (r = .64). With regard to mathematics teachers of intensified general education, these domain-specific dimensions are empirically not distinguishable, whereas CK could be assumed to be a precondition for PCK. In chemistry education research, similar results are missing so far.

The following research questions were focused on:

  • Are there any differences between teachers of different school types regarding their chemistry content knowledge and their pedagogical content knowledge?
  • To what extent do chemistry content knowledge and chemistry pedagogical content knowledge correlate with each other?

For measuring CK and PCK of chemistry teachers (N = 80) paper/pencil tests referring to the same content were developed in this study.

In a first step of PCK item development, open form items were formulated. First, teachers from different school types of different achievement levels (intensified general education and basic general education) were asked to fill out questionnaires and to assess each item regarding its relevance and clearness with the help of a Likert scale. Based on this assessment, adequate items have been picked out for further studies. Furthermore, this study revealed typical answers of teachers for open ended items. In a next step, these answers and respective PCK items were assessed anew using a Likert scale. Therefore, experts of chemistry education and experienced teachers rated the pedagogical content knowledge's correctness of each answer. Four answers whose means were preferably different scaled have been selected for each item to form closed PCK items. It has been considered that the assessment variance of chosen answers was small which means that most experts rated selected answers in a similar way. After this, items in a closed form have been developed which were used for the definite PCK test. To complete the PCK test, teachers were asked to assess the chosen answers by grades from 1 = "very good" till 6 = "unsatisfactory".

This item form allows for successful dealing with the problem of finding PCK answer alternatives which are decisively right or totally wrong. To interpret the new data, a second expert rating was required. Experts of pedagogical content knowledge worked on the same rating scale items as participating teachers. Collected data were analyzed using quasi ranked pairs (Thillmann, 2008). This means that answer classifications regarding given grades of all experts were compared to each other.

The purpose of this comparison was to find rated relations which were rated identically by nearly all experts. Only identically rated relations have been used for analysis of teacher data. Based on this analysis, items indeed have different scores. But it is also assured that only these aspects get points which agree with the experts of pedagogical content knowledge.

13 experts of pedagogical content knowledge were asked to fill out 20 PCK items and assess 80 answers with the help of grades. Between these experts a high reliability (α = .91) is found. Regarding data of all experts an aggregated expert and a ranking of answer alternatives within each item were formed. Out of this, 120 relations of 20 items of each expert were analyzed (α = .91). Accounting low variance (<.5) and high frequency (>.5) of each relation, 61 relations of 17 items have been selected for further analyses.

Preliminary results (N = 51) of the first study with 80 chemistry teachers are described. Underlying data is composed of 50 relations allotted to 16 PCK items (α = .83). The remaining eleven relations do not fit in respect to their solution probability and their separation effect. Differences between teachers of intensified general education and non-intensified general education are significant. Analyzing the whole sample of 51 teachers, a significant correlation of .550** between CK and PCK is found.

Funded by BMBF    

 

Participating Persons

ProWin

Sabrina Witner

Collaborative Project with Oliver Tepner

 

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Video-analyses to determine pedagogical content knowledge of chemistry teachers

The study has only just started

 

Participating Persons

ProWin

Tobias Pollender

Collaborative Project with Oliver Tepner