The Health of the nation outcome scales (HoNOS) [1] were designed to measure the health and social functioning of adults with severe mental health problems. They form part of the English mental health minimum data set and are recommended by the department of health and are part of the attempt to develop “payment by results” (PbR) for mental health [2]. They are also widely used in Australia, New Zealand and Canada [3, 4], and have also been used in Europe [5]. Although they are widely used there are still questions about their psychometric validity and their ability to predict anything useful.
