Significant research has been dedicated to the development of creativity support tools, tools intended to amplify human creativity in the arts, sciences, and design disciplines. While examples of such tools abound, instruments are generally lacking to systematically and reliably assess these tools' impact on the creative process. Without these instruments, it is difficult to identify what aspects of a tool's design most positively affect the creative process. This workshop will focus on the development of evaluation instruments for creativity support tools. From this workshop, we expect a range of instruments to be proposed, explored, and eventually developed. These instruments will range from cognitive assessment instruments (e.g., modified forms of the NASA TLX), to heuristic evaluations for creativity support tools, to techniques that meld with qualitative methods. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation]: User Interfaces