This study investigated whether the number of hours of care needed by a person with disability could be predicted by his or her score on the Functional Independence Measure (FIM) or the Edinburgh Rehabilitation Status Scale (ERSS). Seventy-five subjects (age range, 19 to 65), from a variety of residential services, with neurological disabilities, were visited by an experienced observer to estimate the number of hours of care per week required, from whatever source, for the subject to manage adequately. A second observer, blind to the observations of the first, assessed the subjects' FIM and ERSS scores by interview with the subjects and their carers. Wide ranges of scores on both scales suggested that subjects with many different dependency levels were surveyed, confirmed by "required care hours" varying between 0 and 168 per week (median 18). Pearson's correlation coefficients were 0.36 for ERSS (p < 0.002) and -0.39 for FIM (p < 0.001). Analysis of the scattergrams identified three aberrant cases. Investigation of these showed they each had a high level of dependency due to supervision rather than physical care; exclusion of these cases resulted in much stronger correlations for the remaining 72 cases (ERSS, 0.61; FIM, -0.76). Both ERSS and FIM correlate well with hours of care required, but their association with hours of supervision is poor.