As explained on the University of Wisconsin LEADERSHIP SITE for the Scholarship of Teaching and Learning:

A second part of doing SoTL work is to review the literature that currently exists on the subject we wish to investigate. In short, what have others done that relates to this question? In this stage, one reads existing scholarship in relevant subject areas, reflects on how one's research project builds on the knowledge generated by others, and investigates theoretical frameworks that can guide and frame the current investigation. This stage of the project involves gathering information that can provide important evidence for justifying the significance of your investigatory efforts. This information is typically used to write the rationale or literature review of your final paper.