Background Supervision of children is widely considered a critical factor in injury prevention, yet it is poorly understood.

Purpose This study describes adult opinions about the need for child supervision in various activities.

Methods Data come from a representative survey of US adults. Respondents were asked to suggest the minimum age a child could safely: be left alone in their house; take a bath alone; ride a bike alone in a low traffic area. Respondents who reported having children were also asked if their child had ever been allowed to: play outside alone, or play alone in a room in the house, for more than 10 min; be in the bathtub with another child; and be in a bathtub alone.

Results Overall the mean age that adults believed a child could be home alone was 13 years (95% CI 12.9 to 13.1), bathe alone was 7.5 years (95% CI 7.4 to 7.6), or bike alone was 10.1 years (95% CI 10.0 to 10.3). There were no significant differences by gender or age of respondent. There were significant differences in opinions by income, education, and race. For example, white respondents were significantly more likely to report a younger age (7.2 years) for bathing alone than Hispanic (8.3 years) or African American (8.4 years) respondents.

Significance Assessing adult's understanding of the appropriate age for independent action helps set a context for providing guidance on parental supervision. Guidelines offered to parents should consider social norms as well as child development stages, and messaging can then be tailored by income, education and race.