Designing and validating a blended professional development model for science laboratory management: A mixed-methods study of teachers’ learning and practice

Science laboratory management is an important aspect of science teachers' professional practice but receives limited attention in teacher professional development. This study aimed to develop and preliminarily validate a blended professional development (PD) model for science laboratory management and examine teachers' knowledge, attitudes, and competency enactment. A sequential exploratory mixed-methods design was used, involving needs analysis, expert validation, psychometric evaluation, programme implementation, pre–post assessment, workplace artefact assessment, and qualitative analysis of 15 interviews, reflective OJT journals, and open-ended responses from the participant satisfaction questionnaire. Quantitative data were analysed using Rasch modelling, pre–post comparisons, and N-gain analysis, while qualitative data were thematically analysed and triangulated. The findings provided preliminary evidence of the model's content validity, conceptual coherence, and contextual feasibility. Teachers showed statistically significant pre–post increases in knowledge and attitudes, while participant-level N-gain values indicated variation in the magnitude of individual-level change. Workplace artefacts were generally assessed at good to excellent levels. Qualitative findings indicated that teachers experienced professional learning through learning by doing, movement toward standardized laboratory practices, organizational support and contextual adaptation, and gradual competence development. Authentic workplace artefacts complemented knowledge and attitude measures by providing observable evidence of competency enactment during the programme. The findings provide preliminary evidence of a coherent, practice-connected blended PD model within the study context. However, the one-group pre–post design, small implementation sample, measurement limitations, and lack of long-term follow-up limit causal and generalisable conclusions. Further research using comparison groups, larger samples, and longitudinal workplace evidence is needed to examine the effectiveness, transfer, and sustainability of the model.