The impact of teaching materials on instructional design and teacher development

Abstract

Introduction: Teaching materials are more than just classroom tools — they shape how teachers teach and how they grow professionally. While widely used, their impact across different stages of a teacher’s career has received limited attention. This study explores how different types of materials support both instructional design and professional development, revealing their evolving role across a teacher’s journey. Methods: We conducted a large-scale survey (n = 2,585) of German-speaking educators, all active users of an online educational platform (eduki). The survey included Likert-scale and open-ended items on material usage, instructional impact, professional growth, and classroom confidence. We analyzed the results using factor analysis and MANOVA to identify patterns and differences across career stages. Results: Findings show that instructional impact is highest among trainees (mean = 3.55), while the influence on professional growth increases with experience, peaking among very experienced teachers (mean = 3.91). Teacher-created materials were rated as most useful (90.1%), and teachers reported high autonomy (94.1%) in selecting and adapting materials — a factor closely tied to increased classroom confidence. Two strongly correlated factors emerged from the analysis: “Instructional Effectiveness” and “Improve Me as a Teacher.” Discussion: Rather than plateauing over time, professional development remains vibrant — and even deepens — with experience. Teaching materials play a key role not only in early-career structure but also in later-career reflection and refinement. Empowering teachers to select and adapt resources appears to strengthen both instructional design and long-term growth, challenging traditional linear models of teacher development.