Data quality and age: health and psychobehavioral correlates of item nonresponse and inconsistent responses.

This study examined item nonresponse and inconsistent responses (IRs) and their health and psychobehavioral correlates in a population-based survey of adults 65 years and older. We administered an in-person questionnaire concerning physical, social, and psychological health to 1,155 men (mean age = 73.7 years) and 1,942 women (mean age = 74.8 years). Nonresponse rates varied with item topic, and "don't know" (DK) responses were more common than refusals. DKs increased with age of respondent, tended to be more common in women than men, and were associated with poorer physical, cognitive, and psychological functioning. Conversely, IRs increased with age among men but not women, but were also associated with poorer physical, cognitive, and psychological functioning. Results are discussed in terms of motivational and attentional factors, and their implications for survey research with the frail elderly and very old are noted.