  We describe how graduate students categorize introductory mechanics problems
based on the similarity of their solutions. Graduate students were asked at the
end of a teaching assistant training class to categorize problems from their
own perspective and from the perspective of typical introductory physics
students whom they were teaching. We compare their categorizations with the
categorizations by introductory physics students and physics faculty who
categorized the same problems. The utility of categorization as a tool for
teaching assistant training and faculty development workshops is discussed.
