Blood banks have an ongoing training need and have recently been mandated by the American Association of Blood Bankers (AABB, 1991) to provide competency evaluations of its staff members. Thus, there is an immediate need to develop criteria for training and methods for evaluating the skills necessary to provide quality blood products to patients. There are many medical technology domains that require cognitive task analysis methods for identifying critical aspects of expertise for purposes of assessment and training. Because of rapid changes in technology, highly efficient knowledge assessment strategies are needed. The proposed research will evaluate the feasibility of using a Critical Decision method (CDM) of knowledge engineering to identify and document the assessment skills and training approaches of highly proficient blood bankers. The study will then explore the feasibility of using this knowledge to build training tools and competency tests to meet the needs of blood banks. The results of this project will have direct application to blood banks, as well as more widespread application to meet the training demands of medical technologists and other groups that require training.