There are a number of acceptable methodologies in the psyychometric literature for standard setting studies, also known as cutscores or passing points. Examples include Angoff, modified-Angoff, Bookmark, Contrasting Groups, and Borderline. The modified-Angoff approach is by far the most commonly used, yet it remains a black box to many professionals in the testing industry, especially non-psychometricians in the credentialing field. This post hopefully provides some elucidation and demystification. There is some flexibility in the study implementation, but this article describes a sound method.
What to Expect with the Modified-Angoff Approach
First of all, do not expect a straightforward, easy process that leads to an unassailably correct cutscore. All standard setting methods involve some degree of subjectivity. The goal of the methods is to reduce that objectivity as much as possible. Some methods focus on content, others on data, while some try to meld the two.