25 Getting Inside the Black Box: A tool for diagnostic assessment of interpreters Marlene Elliott Independent Scholar Abstract Interpreters are often assessed, but rarely given diagnostic evaluations capable of guiding their professional development. This paper describes a diagnostic tool based on the belief that the answers to how interpreters improve can be found inside the interpreters. Guided by a respect and understanding for the difficulties of change, the interpreter and diagnostician engage in a collaborative process of dialogue and observation to discover how the interpreter would like to grow and outline a plan to make that growth a reality. By analyzing how the interpreter habitually divides his/her available energy to perform the various, simultaneous parts of the task, ineffective mental habits are discovered and remedies suggested. Finally, a comprehensive professional development plan designed to match the learning style of the individual interpreter is written. Each individual plan provides a framework for professional development that supports deep, lasting growth.