The AMA Guides to the Evaluation of Permanent Impairment, Fourth Edition, includes two methods of evaluating low back impairment following injury, the Diagnosis-related estimates (DRE) method and the Range of Motion (ROM) method. The DRE method should be used first, and the ROM method should be used only when the patient's injury is difficult to categorize or when two examiners disagree about how to categorize a patient. The final rating always comes from the DRE category, never from the ROM method. Two groups of findings help determine into which DRE category to place the patient: First are structural inclusions (eg, fracture patterns on an x-ray) that are objective and automatically place a patient into a DRE category. Second are differentiators such as guarding, loss of reflexes, or loss of bowel or bladder control. In addition, unlisted objective findings may help categorize a patient but may require interpretation; examples include muscle spasm, nonverifiable root pain, anatomical numbness, anatomical weakness, and straight-leg raising. This article discusses the interpretation of sometimes partially subjective findings, thus objectifying them: guarding; muscle spasm; dysmetria; nonverifiable root pain; loss of reflexes; atrophy; straight-leg raising; anatomical numbness; weakness; EMG; loss of motion segment integrity; loss of bowel or bladder control, bladder studies; and range of motion.