Permissible errors in managing property: an approach to the threshold of capacity.

OBJECTIVE: To demonstrate a practical approach to describing the threshold of mental capacity. METHOD: A retrospective analysis of 62 cases of assessments for capacity to manage property was carried out to record the type and frequency of errors. RESULTS: For items on the Mini-Mental State Examination (MMSE), there was no clear demarcation of items associated with a judgement of capable. On the clinical criteria, several items almost completely distinguished capable from incapable subjects. CONCLUSIONS: The permissible error approach makes the threshold of capacity explicit. It is well suited to the emphasis put on functional performance in the evaluation of mental capacity.