The collection and use of data are generally accepted as important educational practices. Nevertheless, evidence exists that interventionists' data collection practices tend to be infrequent and nonsystematic. This study investigated the perspectives of early childhood interventionists about the use of data in their classrooms. Perspectives about the use of data for monitoring children's progress, improving instruction, and communicating with families and other professionals also were studied. Participants were teachers, assistant teachers, and therapists in an integrated setting. Participants identified a number of perceived barriers, including the nature of the setting, management issues, lack of time and skill, and the nature of individualized education programs. Implications for improving the data collection practices of early childhood interventionists are discussed.