The effectiveness of team teaching : experimental research into the effects of team teaching on student outcomes

Team teaching—an educational strategy in which multiple teachers collaboratively plan, deliver, and evaluate a lesson or lessons—is widely promoted as an approach to enhance student outcomes. However, key questions about the effectiveness of team teaching—particularly whether, when, for whom, and how, it works—remain insufficiently addressed. This PhD dissertation examines not only the overall effectiveness of team teaching on student outcomes but also the mechanisms through which it may exert its effects, using experimental research. The dissertation comprises four interrelated studies. Study 1 presents a systematic review assessing the conceptual and methodological credibility of experimental studies in team teaching research. The findings highlight a persistent lack of rigorous, well-defined experimental research, leading to recommendations for improving future studies on the effectiveness of team teaching. Study 2 involves a crossover experiment with 267 primary education students comparing student achievement in team-taught versus solo-taught lessons, while also exploring moderating influences of student, outcome, and contextual factors. The results show that students perform slightly better in team-taught lessons, though the effects are modest and reduced when the student-teacher ratio increases. Study 3 investigates how team teaching influences student achievement by examining whether students' basic psychological needs and lesson engagement mediate this effect. The results show that team teaching improves students’ feelings of competence, which partly explains team teaching’s positive impact on achievement, while autonomy, relatedness, and lesson engagement do not significantly mediate the relationship. Study 4 adopts a qualitative approach, capturing students’ perceptions on their experiences with both team teaching and solo teaching. The findings show that students experience more support and better learning opportunities with team teaching; however, its effectiveness is influenced by the class size—with smaller classes showing clearer benefits and larger classes leading to more distractions and weaker teacher-student connections. This dissertation offers a comprehensive and nuanced understanding of the effectiveness of team teaching and the processes through which it influences student outcomes, while advancing methodological standards in team teaching research.