In the absence of such an index, the committee is reluctant to recommend prevention strategies that favor one disabling condition over another. However, in succeeding chapters the committee cites some of the needs and issues related to several categories of individual disabling conditions.
Major gaps exist in the data and knowledge about risk factors associated with disability. One reason for these gaps is that most disability-related data are oriented toward clinical categories or impairments. Such categories may have clinical utility for addressing the treatment needs of persons with specific impairments, but they are not useful in fostering an epidemiology based on risk factors such as those related to the social and physical environment.
As discussed earlier (under the section on risk factors), the committee believes that specific conditions may not always be the most appropriate or effective means for setting priorities or identifying targets for the development of preventive intervention strategies. An alternative method for consideration is to focus on risk factors or causes that are generic to the etiology of several disabling conditions. Some examples include smoking, alcohol abuse, drug abuse, socioeconomic status, and lack of prenatal care (see Table 3-2). These risk factors are already associated with many of the nation's leading health problems. Less understood is their relationship to disability.
Cause-oriented disability data need to be considered possible alternatives in the development of approaches to identifying priorities in disability prevention.
The standard public health model delineates three categories of prevention efforts—primary, secondary, and tertiary—each one focusing on distinct stages in the natural history of diseases. This same model is applicable to the prevention of disability. And, as is true for all prevention programs, epidemiological data and analyses are the cornerstones of effective planning and evaluation. Thus the quality and quantity of the available epidemiological data, as discussed in the previous section, will be critical to the development of effective intervention strategies. Here, the committee briefly summarizes the primary, secondary, and tertiary approaches to prevention and how they might be applied to disability (see Patrick and Peach  for additional information). Prevention efforts that are specific to various disabling conditions are discussed in more detail in succeeding chapters.
Primary prevention focuses on healthy persons, seeking to avoid the onset of pathological processes by reducing susceptibility, controlling exposure