In addition to patients and their families, doctors also are confronted with ethical questions. In addition to patient life, doctors have to consider medical resource allocations. They have to decide whether one patient is a worthwhile investment of limited resources versus another. Current ethical guidelines are vague since they center on moral issues of ending medical care but disregard discrepancies between those who understand possible treatments and how the patient's wishes are understood and integrated into the final decision. Physicians often ignore treatments they deem ineffective, causing them to make more decisions without consulting the patient or representatives. However, when they decide against medical treatment, they must keep the patient or representatives informed even if they discourage continued life support. Whether the physician decides to continue to terminate life support therapy depends on their own ethical beliefs. These beliefs concern the patient's independence, consent, and the efficacy and value of continued life support. In a prospective study conducted by T J Predergast and J M Luce from 1987 to 1993, when physicians recommended withholding or withdrawing life support, 90% of the patients agreed to the suggestion and only 4% refused. When the patient disagreed with the physician, the doctor complied and continued support with one exception. If the doctor believed the patient was hopelessly ill, they did not fulfill the surrogate's request for resuscitation. In a survey conducted by Jean-Louis Vincent MD, PhD in 1999, it was found that of European intensivists working in the Intensive Care Unit, 93% of physicians occasionally withhold treatment from those they considered hopeless. Withdrawal of treatment was less common. For these patients, 40% of the physicians gave large doses of drugs until the patient died. All of the physicians were members of the European Society of Intensive Care Medicine.