Abstract
This paper describes a PhD research project which addresses the issue of quality aspects of dynamic materials. Platforms with user-generated educational resources for mathematics teaching show a wide variety in terms of quality of materials. The presented project investigates possible quality criteria for dynamic materials based on the opinion of experts who describe their views on educationally valuable use of dynamic materials. The results of this study should give new inputs and ideas for designing manual and/or automatic review systems for dynamic material platforms such as GeoGebraTube.