Volunteer resident physicians and faculty carried data collection checklists in their pockets and completed one for every adolescent patient seen during a randomly selected two week period. Physicians attempted to collect data on ten consecutive encounters with teen patients aged 11-21 years. The checklist documented patient characteristics (age, gender and ethnicity), reason for visit, parent presence, and types of prevention issues discussed during the visit. Patient and visit information was collected to assess its influence on physician prevention discussions. Finally, the checklist asked open-ended questions related to barriers to and facilitators to teen prevention discussions.