We report on a study of a laboratory teaching apprenticeship program designed to improve graduate teaching assistant (GTA) performance. To catalyze GTAs as laboratory teachers we constructed learning goals, synthesized previous literature into a design model and a developmental path, and built two instruments to measure 12 strategic pedagogical interactions. The resulting model is a cognitive apprenticeship. The instructors encourage GTAs to teach chemical knowledge by guiding their undergraduates' reasoning—in addition to explicit transmission of chemical knowledge. The new graduate course was refined over 5 fall semesters and 83 graduate students. Qualitative audio-video supplemented statistical data. Valid and reliable data, collected from coding 12 strategic interactions while GTAs taught a lab, were used to judge effectiveness of teaching in terms of pedagogical chemical knowledge (PChK). Three types of laboratory PChK are defined and described. The results show that 45% of new GTAs developed higher forms of PChK. Exemplary GTAs found that the extended time in lab is an advantageous occasion to teach UGs how to reason with chemical concepts; their actions utilized a constructivist learning model focused on directing students to reason, thereby increasing students' abilities to reason. Some 8% of new GTAs developed only the lowest form of PChK, procedural teaching.
Assessments of teaching quality by undergraduates (UGs) and faculty are illustrated in this study of new graduate students training as TAs (GTAs). The GTAs' instructors (FAC) coached them while they taught labs, and coded teaching interactions on the valid and reliable ITAT instrument (Cronbach's a = 0.863). Interactions were documented by a remote audio-visual observational system. Audio-visual clips and ITAT feedback were used to foster GTAs' development in managing a chemical lab procedurally, and teaching chemical concepts. The UGs assessed their TA with the UGATA instrument (Cronbach's a = 0.953). Our research compared the FAC rating of GTAs to UGs' end-of-semester ratings. The UG and FAC ratings were similar on procedural management interactions, but not on concept teaching. The FAC saw significantly less quality in GTAs' interactions that linked concepts from lecture into lab and explained abstract concepts basic to the lab experiment. In fact, UG ratings failed to note significant differences between teaching of procedural knowledge and teaching of abstract concepts that were fundamental chemically to the lab experiment. While over 75% of GTAs executed management interactions well, only 30–40% of GTAs were actively attempting to teach concepts and to help UGs reason conceptually in chemistry.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.