In most mental hospitals some attempt is made to effect change among long-stay patients. This problem in rehabilitation has been approached in several ways, but irrespective of individual approach it is desirable to have some assessment of the degree of change accomplished. Social aspects of behaviour, rather than symptoms, are the target of such rehabilitative efforts, and nurses play an important part both in pursuing the goals of treatment and in assessing change in individual patients. The NOSIE (Honigfeld and Klett, 1965; Honigfeld, Gillis and Klett, 1966) is a particularly well-developed rating scale whose content has been tailored to the task of assessing change in long-stay patients and has been successfully used for this purpose in the United States. In its present form it comprises 30 items which form 6 scales: namely, Social Competence, Social Interest, Personal Neatness, Irritability, Manifest Psychosis and Retardation. This note is concerned with three questions which the British user should ask before using the scale; does it do what it claims to do, does it do it accurately, and what range of scores could be expected in a British hospital population.