The development of a new method of knowledge assessment: tailoring a test to a doctor's area of practice.

The practice of clinical medicine is becoming increasingly specialized, and this change has increased the challenge of developing fair, valid, and reliable tests of knowledge, particularly for single candidates or small groups of candidates. The problem is particularly relevant to the UK's General Medical Council's Fitness to Practice procedures, which investigate individual doctors. In such cases, there is a need for an alternative to the conventional approach to reliability estimation that will still allow the delivery of reproducible and standardized tests. This report describes the three-year process (starting in 2005) of developing a knowledge test that can be tailored for individual doctors practicing in narrowly specialized fields or at various stages in their training. The process of test development for this study consisted of five stages: item writing, to create individual questions; blueprinting, to establish the content and context that each item might test; standard setting, to calculate for each question a theoretical probability that a doctor of just-adequate capability would answer the question correctly; reference data collection, to determine for each item the distribution of scores to be expected from a large population of doctors in good standing; and test assembly, to select sets of questions that together formed complete and balanced tests. Tailored testing is a valid, feasible, and reproducible method of assessing the knowledge of one doctor or small groups of doctors who are practicing in narrow or subspecialty areas.