The Impact of Teaching Materials on Instructional Design and Teacher Development

Lola Garay Abad ^1* John Hattie ²

• ¹ eduki, Berlin, Germany
• ² The University of Melbourne, Parkville, Victoria, Australia

This study presents a comprehensive analysis of the dual role of teaching materials in supporting both instructional design and teacher professional development. Through a largescale survey (n=2,585) of German-speaking educators across multiple subjects and experience levels, all users of an online set of resources combined with meta-analytical frameworks, we identify distinct patterns in how teaching materials influence teacher development across career stages.Our findings highlight the nuanced role of teaching materials in shaping both instructional design and professional development across teacher career stages. The influence of teaching materials on instructional design is most pronounced among trainees (3.55 on a 4-point scale), with a slight decline as teachers gain experience (3.47 for very experienced teachers). In contrast, the impact on professional growth remains consistently high (3.82) and even increases among very experienced educators (3.91), underscoring the sustained importance of materials in ongoing development. Teacher-generated materials emerge as the most impactful, with 90.1% of teachers finding them extremely or quite useful, compared to 70.1% for publisher materials and just 38.6% for institution-produced content. Additionally, 94.1% of teachers report having autonomy in selecting their materials, reflecting strong teacher agency. This autonomy correlates with increased classroom confidence, particularly when using self-created resources (79%), compared to publisher (51.2%) and institution-produced materials (30.5%).These insights suggest that empowering teachers to create and select their own materials enhances instructional design and fosters professional growth and confidence in the classroom.