Research Objective: Data indicate that screening rates for colorectal cancer (CRC) in the United States are less than the goal of 50 percent outlined in Healthy People 2010. Physician recommendation is an important predictor of patient’s compliance with CRC screening tests. The purpose of our research was to compare colorectal screening decisions made by individual physicians and determine how variations in their decision processes impact decision outcomes. Further, we examined whether those variations could be attributed to physician’s characteristics and guidelines’ utilization.

Study Design: We conducted semi-structured interviews with primary care physicians, developed decision trees, compared trees, used trees to predict the recommendation for eight vignette patients, and employed regression analysis to identify predictors of variation.

Population Studied: We interviewed sixty-six primary care physicians (59.1% internal medicine and 40.9% family practice).

Principal Findings: Most of the physicians (77.3%) self-reported following clinical guidelines for CRC screening. Physicians considered an average of 5.9 decision criteria (range 2-12) in making their screening recommendations. Frequently cited criteria included patient age and family history. We documented variation for three of eight vignette patients. Regression analysis indicated that complexity of decision process, gender, age and experience of physicians contributed to recommendations on screening. In addition, the self-report adherence to guidelines did not influence whether a physician would recommend CRC screening.

Conclusion: This study supports the notion that variation in practice is a function of decision processes.

Implications for Policy, Delivery or Practice: Studying decision processes may facilitate efforts to improve patient outcomes.