Introduction: Students’ peer relatedness is vital to their academic achievement and engagement. However, little is known about the mechanisms that can explain such a link in health professions education, especially in interprofessional education (IPE), where interprofessional socialization is promoted. To address the research gap in understanding the social dynamics embedded within IPE and their impact on crucial motivational outcomes, this study examines how peer relatedness (belonging) mediates the link between motivation (both intrinsic and extrinsic) and engagement in IPE. Methods: Data from 841 students enrolled in IPE from Medicine, Nursing, Social Work, Chinese Medicine, Pharmacy, Speech and Hearing Sciences, Clinical Psychology, and Food and Nutritional Science from a university in Hong Kong were used in this study. Intrinsic and extrinsic motivation were collected at baseline, while peer relatedness need satisfaction and engagement and disaffection in IPE were assessed after four weeks. We used a fully latent structural equation model to examine whether peer relatedness mediated the link between motivation and engagement in IPE. Results: Our results indicate that intrinsic motivation at baseline significantly increases engagement and reduces disaffection four weeks later, while extrinsic motivation shows the opposite effect. Crucially, the adaptive role of motivation to engagement was significantly mediated by relatedness from IPE teams. Specifically, the effect of students’ motivation on their engagement/disaffection in IPE can be partially explained by their relatedness within IPE teams. Conclusion: This study underscores the importance of peer relatedness in IPE, highlighting its role in harnessing student motivation to foster student engagement. The findings contribute to a deeper understanding of the psychosocial mechanisms in IPE and highlight the value of collaborative learning environments in fulfilling students’ need for relatedness, thereby fostering

Collaborative lesson planning (CLP) is a key component of teachers’ professional development that responds to students’ ever-increasing learning needs. This study aimed to develop and validate an instrument to evaluate teachers’ CLP practices. Guided by the SECI (socialisation, externalisation, combination, and internalisation) knowledge-creation model of Nonaka and Takeuchi (1995), items assessing CLP practices were developed. To validate the CLP scale, we analysed data from 540 primary and secondary school teachers in Hong Kong. Exploratory factor analysis on a random half of the sample suggests a four-factor solution that supports the SECI model. A confirmatory factor analysis and multidimensional Rasch analysis on the remaining half of the sample confirmed the four-factor structure. Both analyses support the dimensionality of the four-factor model, rating scale effectiveness, and item fit statistics. The final version of the CLPS has 21 items that assess teachers’ CLP practices under the four SECI processes. This instrument has practical value in assessing, monitoring, and promoting collaborative teaching practices in school. The study's limitations and implications are discussed. Copyright © 2022 Elsevier Ltd. All rights reserved.