The Approved Guide, in the section “Principles of Assessment”, includes the following general discussion of the Impairment Tables:
Part A of the Guide is based on the concept of 'whole person impairment' which is drawn from the American Medical Association's Guides.
Evaluation of a whole person impairment is a medical appraisal of the nature and extent of the effect of an injury or disease on a person's functional capacity and activities of daily living.
As with the American Medical Association's Guides, Part A of this guide is structured by assembling detailed descriptions of impairments into groups according to body system and expressing the extent of each impairment as a percentage value of the functional capacity of a normal healthy person. Thus a percentage value can be assigned to an employee's impairment by reference to the relevant description in this guide.