[Responsiveness of outcome measures].

In medical research, particularly in the field of rheumatology, there is great interest about the concept of responsiveness of outcome measures as a sign of changes in the patient's health status. However, the terminology sorrounding this concept and the methods of analysis are confusing and lacking in consensus. We present a review about the concept and analysis of responsiveness taking into account both, the characteristics of the responsiveness and the type of design and predictable change in the sample being studied.