An impairment is defined as "a loss, loss of use, or derangement of any body part, organ system or organ function". The impairment evaluation should be performed by physicians. To determine permanent impairment associated with medical condition a standard method should be used. It is a general principle that an evaluation of permanent impairment only be performed when the physician considers the person to have reached a state of maximum medical improvement. Maximum medical improvement is considered when the person's condition has been medically stable and is unlikely to change by more than 3% of whole body impairment within the next 12 months. The physician must use the entire clinical skill and judgment to perform the proper impairment evaluation. A report of the evaluation of permanent impairment should be accurate, comprehensive and fair. The physicians are reminded that they have a duty to act in an ethical, professional and considerate manner when examining the person for the purpose of assessing the permanent impairment.