Santa Catalina Island, California. June 13, 2009.

The physical domain contains a wide range of limitations, but generally relates to respiratory, metabolic, and musculoskeletal body functions associated with movement. The [2008 American Community Survey] focuses on ambulatory difficulties in question 17b of the 2008 questionnaire, which asked respondents aged 5 years and older, “Does this person have serious difficulty walking or climbing stairs?” In 2008, about 19.2 million people or 6.9 percent of the civilian noninstitutionalized population 5 years and older had an ambulatory difficulty …

For estimates of ambulatory difficulty, the [2008 Survey of Income and Program Participation] provides degrees of severity against which the ACS measure can be portrayed. Whereas the ACS measure asked about serious difficulty walking or climbing stairs, the SIPP measure asks about difficulty with each activity and follows up with questions about whether the respondent can perform the activity at all. The resulting measures show two levels of difficulty walking or climbing stairs. As shown in Figure 8, the ACS ambulatory difficulty measure falls in between the two SIPP measures, implying that it may capture difficulty that is more severe than the basic SIPP measure of difficulty walking or climbing stairs, but less severe than the measure of being unable to perform at least one of the activities.

Excerpted from Review of Changes to the Measurement of Disability in the 2008 American Community Survey by Matthew W. Brault. Published by the U.S. Census Bureau, September 22, 2009.