ity monitoring system is not simply measurement of the prevalence and of the socioeconomic conditions linked to disability, but also understanding both the individual and the environmental factors that lead to changes in the application process. This chapter explores ways in which SSA could build from its experience with the NSHA to develop an ongoing disability monitoring system for Social Security programs to provide timely information on the prevalence and distribution of disability in the working population. This chapter discusses the need for such a system, essential principles of such a system, possible design choices, and a suggested planning and implementation strategy.

A well-designed monitoring system should provide SSA with the data needed to respond to a variety of policy and planning issues, including, but not necessarily limited to, the following:

1. Size, distribution, and characteristics of the working populations with disabilities. The growth in the population eligible for SSDI and SSI during the past three decades and the concomitant growth in applicants and awards have raised questions as to whether continued expansion of these programs can and should be sustained.

2. Demographic trends. The working age population has grown dramatically and its composition has undergone fundamental change since the inception of the SSDI and SSI programs. This working age population eligible for disability benefits is projected to increase in the coming years as the baby boom generation ages and reaches the ages at which chronic diseases and disabilities are more likely to occur. This growth will impact significantly the Social Security disability programs in many ways.

3. Labor market dynamics. Structural changes in the economy such as the relative shift over the years to service industries and occupations have a significant impact on the types of impairments that result in work disability. Labor force participation rates among women have increased substantially while those of men have declined. These structural changes need to be fully understood and predicted accurately.

4. Changes in economic conditions. During periods of slowdown in the economy and high unemployment, marginal workers especially low-wage workers with disabilities are more likely to apply for disability benefits. SSA needs to closely monitor these changes in economic conditions and their impact on Social Security disability programs.