Advances in electronic medical record capabilities enable clinical reminders to inform providers when recommended actions are "due" for a patient. Despite evidence that they improve adherence to guidelines, the Veteran's Health Administration (VHA) has experienced challenges in having providers consistently use clinical reminders as intended. In this paper, we describe how multiple methods were used to opportunistically triangulate, or "bootstrap," an understanding of barriers to the effective use of clinical reminders in the VHA. In an initial study using ethnographic observations and semi-structured interviews of HIV clinical reminders, we identified six barriers to effective use: workload, time to remove inapplicable reminders, false alarms, training, reduced eye contact, and the use of paper forms rather than software. In a second study, we collected open-ended and closed-ended data regarding barriers and facilitators to the use of clinical reminders in general in the VHA through a survey of 261 participants at a national informatics meeting, where 104 of 142 VHA health care facilities were represented. The findings from the second study extended our understanding of the previously identified barriers. In addition, four new barriers were identified: ease of use issues, accessibility of workstations, resident physicians and trainees, and administration benefiting more than providers from clinical reminder use. We discuss potential implications regarding the similarities and differences in study findings for factors to consider in planning interventions to improve clinical reminder use.