A study was made of background, personality, and other characteristics as related to aptitude test performance among Swedish adults attending evening schools, state secondary schools for adults, and county colleges, and among those pursuing correspondence courses. Test results were significantly related to age, sex, and dropout status (interruption of studies). Differences on personality variables were related to age and sex only. Respondents' choice of type of school was determined most strongly by age and educational background as well as the possibility of working while studying. Among other things, it was also found that adult students achieve results on aptitude (especially verbal) tests superior to results in comparison norm groups. Implications for recruitment and curriculum planning were stated. (Five references and seven tables are included.) (LY)