nent of the ICF is accompanied by instructions for rating. Like the ICD, the ICF version has an alphanumeric coding system. The component, domain, item, and subitem are identified to the left of a decimal. To the right of the decimal, the coding structure contains space for qualifiers such as difficulty in performing activities or in being involved in life situations.
Impairments in ICF body functions are rated by one qualifier as the extent of the impairment on a five-point scale from “no impairment” (0) to “complete” (4), with mild, moderate and severe being 1, 2, and 3, respectively. This is generally thought of as a clinical rating, with the threshold determined by clinical expertise. Body structures have three qualifiers. The first is identical to body functions. The second qualifier uses nominal coding to describe the nature of the impairment. For example, 1 is used to indicate that there is a total absence of the body structure as in an amputated limb, 4 indicates aberrant dimensions of the body structure, and 6 denotes a deviation in the position. The third qualifier for body structure identifies the location of the impairment. For instance, 0 specifies that the impairment is in more than one region, 1 that it is on the right, 4 that it is in the front, and 7 that it is distal. Using all three qualifiers provides a rich description of the extent, nature, and location of the impairment of body structure.
Activities and participation have two qualifiers: performance and capacity. The first qualifier is performance, which demarks how much difficulty the person experiences in executing the task or being involved in a life situation as conducted in her or his usual day-to-day life. This means how and where the person spends time doing things. The second qualifier is capacity, which describes the person’s ability to execute a task or action. Capacity is assessed in a formal test setting that is standardized to evaluate the true ability without the influence of the environment. Thus, capacity is considered to be evaluated in a neutral, standardized, or uniform environment. Variations of these two qualifiers indicate whether or not the person is using assistive devices or personal assistance in the assessment. Coding for both performance and capacity qualifiers is identical to body functions and to the first qualifier of body structures: it identifies the degree of difficulty.
In the structure of ICF qualifiers, there is room for consideration of additional qualifiers. It is anticipated that some users of ICF may develop their own qualifiers to suit their programmatic or other needs. For example, the SSA may wish to consider application of these or other qualifiers—or the development of an explicit algorithm using qualifiers—in refinement of the B criteria or revision of MRFCA.