Nieveen's model, primarily referred to as CASCADE (Computer Support for Curriculum Developers), is essentially an electronic performance support system (EPSS) intended to improve the effectiveness and quality of curriculum materials development (Gustafson). The origins of CASCADE were inspired by the process of educational change from the levels of national policy to classroom implementation. A study was undertaken in 1993 between the National Institute for Curriculum Development (SLO) in the Netherlands and the University of Twente to focus on "develop[ing] a computer support system which assists curriculum developers from the SLO in optimizing the effectiveness of their formative curriculum evaluation efforts, within a framework of a more comprehensive model of curriculum development." (Nieveen, 1997) One goal for CASCADE's usability was for it to serve as more of a "toolbox" for curriculum developers rather than something prescriptive. Tools such as templates and frameworks are available with some adaptability to individual users. (Nieveen, van den Akker, 1999)