Recruiting African Americans into research on cognitive aging.

A total of 218 adults with an average age of seventy-eight years participated in a study of memory performance in community elders. A computer-generated random zip code list of adults > or = 70 years of age was purchased and a four-phase telephone-screening plan was adopted. During the second year, the sampling plan had to be changed, with a convenience-sampling plan being adopted to recruit adequate numbers of African-American subjects. Fifty-seven percent of the African-American subjects (N = 55) and 68% of the White subjects (N = 83) were recruited from random sampling methods. As compared to the random sample, the convenience sample was significantly older (80 vs 76), had more depression (12 vs 9), had lower physical functioning (46 vs 65), and less vitality (48 vs 60). On meta-memory, the convenience sample scored higher than the random sample on achievement (3.84 vs 3.69), and lower on task (3.75 vs 3.85). The convenience sample scored significantly lower than the random sample on memory performance (15 vs 18), and memory self-efficacy (26 vs 33). More research is needed to document normative measures for cognitive function and to facilitate accurate comparisons between African-American elderly and other elderly.