The state of Illinois has undergone major workers’ compensation reform with the passage of House Bill 1698, and from September 1, 2011, one of the factors used to determine a permanent partial disability (PPD) rating is an impairment evaluation according to the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition. Previously, the Illinois Workers’ Compensation Commission used a body of case law that set forth general parameters to guide PPD assessment, and the Commission would not allow testimony for any doctor's opinion regarding the percent of disability. Adding the use of the AMA Guides should increase the reliability of these awards. Impairment rating is only one factor that will be considered in determining the level of PPD, and other factors include the injured employee's occupation; age at the time of injury; the employee's future earning capacity; and evidence of disability corroborated by the treating physician's medical records. No single factor should be the sole determinant of disability, and the fact finder must use judgment and must document the rationale for the decision. Basing the impairment rating on the AMA Guides as a starting point should result in both a more valid and more reliable process to determine PPD.