In order to determine the criteria by which health care, legal professionals, and informal caregivers who care for older persons make decisions to seek guardianships, a 22-item scale developed by the investigators was distributed to decision-makers. Responses from 206 caregivers were evaluated using descriptive statistics and robust ANO VA. Of most importance to determining incapacity were criteria related to endangerment of self or others, and of least importance were criteria involving activity levels and social participation. Decision-makers were in agreement about nine of the 22-items, and disagreed about the remaining thirteen. Informal caregivers were generally less willing than professionals to indicate that criteria were highly important to incompetence. The close and intimate relationships informal caregivers have with older relatives or friends as opposed to the more formal relationships that health care and legal professionals have with them might affect judgments about when proxy decision-making is needed.