This chapter describes the test design is the process by which key stakeholders make decisions about the plan for the development, administration, and maintenance of the test. It examines how the design process should be conducted, what decisions should be made, the inputs to each, and the impact of each outcome. The chapter describes there are a number of goals but also constraints that should be considered when making each of the critical decisions and therefore, it is important that parties representing all critical factors be a part of the decision-making process. This is a conjunctive model as the performance scores are combined to determine the overall decision. This model requires a bit more work during the content specification/blueprint development, standard setting, and score reporting processes, but may provide stakeholders the reassurance that candidates have demonstrated competency in several key areas and that the evaluation of a candidate's knowledge base in each area results in a reliable decision.