Looking for important change/differences in studies of responsiveness

The purpose of this paper is to describe a classification system for studie s of responsiveness that was designed to help organize these studies, and i dentify those with the potential to provide information on minimal clinical ly important difference (MCID). We developed a 3 dimensional cube into whic h studies of responsiveness can be categorized based on their evaluation of 3 attributes: 1. individual or group setting; 2. which scores are contrast ed; and 3. the type of change or difference being assessed. We present and discuss examples of studies that fit into categories in the classification cube. This classification system helps to focus attention on whether the li terature is able to provide information on the specific type of change a pe rson is interested in. It reinforces that the ability of an instrument to d etect a certain category of discrimination within the cube does not mean it will necessarily be responsive to another category. The cube has been show n here as a means to separate out studies that address important change. Th ese studies can then be examined as the source of information on MCID.