Validation of health status instruments.

Health status instruments are questionnaires that are utilized to assess changes in health status of individuals. These surveys are increasingly of importance as health care providers are challenged to justify treatment approach and rationale. Objective criteria (e.g. CT scan of the sinuses) can be used to determine whether there is clinical evidence of disease. However, the impact of the disease on the individual's life is not included in such a clinical assessment. The use of validated and reliable health instruments is directed at measuring this impact in a reproducible and valid fashion. In patient-centered research, 'experimental' conditions are constantly changing because we are dealing with human beings with values, feelings, and perspectives. It is especially important to use valid measurement tools when assessing these impacts. This article outlines the principles of the development and validation of health status instruments and offers examples of such instruments from the otolaryngology literature.