UDL Research
UDL Guidelines Version 1.0: Research Evidence
The UDL Guidelines (v1.0) are based on research from several very different fields and from diverse researchers at many different universities and research organizations. That research has been reviewed, compiled, and organized by educators and researchers at CAST: 
http://www.udlcenter.org/research/researchevidence.
The process spanned a 10 year period and involved several different stages.
Stage One: The first stage constructed a general framework for UDL and its guidelines. The research basis for that framework came primarily from modern research in the learning sciences: cognitive science, cognitive neuroscience, neuropsychology, neuroscience. The focus of that phase was on identifying the range and sources of variance in human learning—what are the individual differences that an adequate pedagogy must address? The three basic learning networks and principles of UDL were distilled from that review.
Stage Two: The second stage articulated those three basic principles further—identifying the most important categories within them that would need to be addressed in an adequate pedagogy of individual differences. The review of the research led us to the development of the nine UDL Guidelines.
Stage Three: Using that framework as a guide, the third stage involved over three years of extensive reviews of the educational research to identify those specific practices that are most effective in reducing barriers to instruction in each of the principles. This compilation began first by gathering existing reviews and meta-analyses of research and best practices to set the landscape. Following that, we began extensive secondary searches of the literature using keywords and concepts suggested by the meta-analysis and reviews. Nearly 1,000 articles were eventually reviewed and selected for inclusion in the evidence base that is now organized around each of the checkpoints in the UDL guidelines.
Within each checkpoint, the supporting research is organized into two categories:
- Experimental and quantitative evidence
- Scholarly reviews and expert opinions
See also our UDL and AIM page at http://aim.cast.org/experience/acrosscurriculum/udl for background information about UDL and resources related to UDL and AIM.