My study focused on developing an instrument to resolve a problem of practice in my organization: How to accurately match individuals' preferences with projects. Other project leaders and I had already identified four 'types' of project preferences. My study used those constructs and their defining characteristics to develop a new instrument: The Project TWIST Test. Because I had extensive experience leading project teams, the temptation was to assume that the defined constructs and phrases were already reliable and valid. However, true instrument development requires a more thorough, systematic approach. This case study provides an overview of the instrument's development following the process outlined by Sandra A. McIntire and Leslie A. Miller. The case demonstrates how I applied these test development steps. It also reviews how I determined how much of the instrument development process could be covered in one study. [This content is provided in the format of an e-book.]