This study used interviews and classroom observation to follow up a survey of 78 Head Start staff from five programs in the mid-Atlantic region. The purpose of the study was to collect additional details about administrator and staff needs in regard to addressing children's challenging behavior in order to design a PBS in-service intervention. Interviews were conducted with 45 adults from the same preschool sample, and direct observation occurred in 10 classrooms. Similar to prior survey results, it was found that interview respondents (a) listed externalizing behaviors as the predominant challenging behavior, (b) identified prevention and replacement methods for addressing problem behavior, and (c) indicated that families of children with challenging behavior were given opportunities to be involved in intervention planning and implementation. However, interview and observation results further exposed the use of reactive practices and revealed five primary barriers to addressing children's challenging behavior. Finally, interview respondents reported that all programs had defined procedures they followed when children exhibited challenging behavior that in most programs was based on a traditional, child-focused, mental health approach rather than on a comprehensive systems approach like positive behavior support. (Contains 1 table.)