Specific Wording of Question, Response Option Presentation, and Overall Context Although there is empirical evidence to indicate that estimates of the population differ as a result of different question wording, the presentation of response alternatives, the order of questions, and the overall context of the questionnaire, little is known concerning the measurement error properties of alternative approaches, nor is there empirical literature that addresses the marginal effects of various question design features.
As is evident from the design choices discussed above, each choice impacts the error structure of the estimates of persons with disabilities and the analytic capabilities that can be addressed with the resulting data. Also evident is the lack of information with respect to the specific impacts of design choices on the reporting of impairments and disabilities; this point was one of several made in the Workshop on the Measurement of Work Disability (Mathiowetz and Wunderlich, 2000).
One could consider a number of permutations of the options outlined above in designing a work disability measurement system; these options could be arrayed along lines of richness of the data, quality of the data, and costs. For example, consider a system with the following attributes:
continuous, longitudinal multimode household-based data collection (so as to facilitate participation among those who are unable or unwilling to answer via a single mode);
medical examination for those meeting a particular threshold based on the household data and a subset of those who are classified in the category adjacent to the threshold; and
links to administrative records.
Such a design would facilitate the analysis of change over time in the size of the pool of eligibles and applicants, and the understanding of the individual and environmental factors that influence application for benefits, and could simulate the impact of alternative decision processes, provided the household survey, medical examination, and administrative records collected or contained the information necessary for such modeling. In contrast, one could consider a design that is characterized by a small number of questions on disability included as part of repeated cross-sectional surveys. Such a design would limit analysts to monitoring the size of the pool of eligibles and possibly, if cross-walk analytic capabilities had been developed, the size of the pool of applicants. However, such a design does not facilitate understanding how individual, environmental, and macrolevel changes impact the application process; with such a design one can only observe a correlation between macrolevel changes and changes in the size of the applicant pool, but cannot understand the