Abstract

To assess the differences between actively recruited and “opt-in” participants with respect to baseline characteristics and behaviors related to an intervention targeting TV habits, participants were compared on demographics, parental TV attitudes, child behavior, and amount of screen time. Statistically significantly larger proportions of active recruits were non-white, from a low-income family, more likely to have TVs in the bedroom, and on average, spent more time viewing frightening or violent TV content. Many characteristics are comparable between the two groups but there are some factors that had small but significant differences. It may be possible to rely on a modified passive recruitment approach where certain demographic groups are targeted and oversampled to approach a population that is comparable to an actively recruited study sample.

Key words: Recruitment methods, bias, behavioral intervention, preschool- aged children, television, opt-in.