ture for developing questionnaire items designed to capture environmental factors that affect the disablement process. Among the environmental factors of importance in the ICF framework are products and technology, the natural environment, support and relationships, attitudes, social services, systems, and policies. Of interest with respect to disability is the extent to which environmental factors either facilitate or present barriers to participation in social roles. As part of the research to design questionnaires that map conceptually to the ICF coding framework, researchers are currently addressing the development of both objective and subjective environmental measures (Schneider, 2001).
The committee underscores the need to develop measures of both the physical and the social environments. The measurement of environmental context should examine both factors that accommodate impairments and those that serve as barriers. The development of objective measures of the physical environment may be facilitated by fostering collaboration with researchers in ergonomics and human factors engineering, fields in which a primary focus is the measurement of the environment.
To aid in the development of objective measures of the social environment, the committee notes the need to develop and test questions concerning social climate, barriers, and stigma. These questions are especially important for those with mental illness, but they are relevant for, and should be asked of, all persons with disabilities.
One of the challenges related to developing objective measures of the environment is the identification of a set of questions that can be asked of the general population. However, to fully understand either barriers to employment or factors that facilitate employment, questions must be tailored so as to be relevant to the individual’s situation. Ethnographic exploratory studies of workplace environments are one means by which to inform household measurement of accommodation and barriers. For those who are no longer working, questions that enumerate what accommodations would be necessary to facilitate, or what barriers prevent, participation in the workforce have to be designed and subjected to evaluation. Similarly, research is needed on developing subjective measures of both the physical and the social environments that either facilitate or limit participation.
In addition to research for developing such measures of the environment, research also is needed on two additional topics: (1) assessment of systematic differences in evaluating the environment among those for whom the environment is benign versus those for whom the environment is hostile and (2) assessment of the difference between self and proxy subjective reports of environmental conditions.
To summarize, the empirical literature examining measurement error associated with specific questions, albeit limited, suggests that items cur-