In logistic regression models of colonoscopy overuse, an endoscopist recommendation for early follow-up was strongly associated with overuse of screening colonoscopy (OR 6.27, 95 % CI: 3.15-12.50) and surveillance colonoscopy (OR 13.47, 95 % CI 6.61-27.46). In a multilevel logistic regression model, variation in the overuse of screening colonoscopy was significantly associated with the endoscopist performing the previous exam.

http://www.ncbi.nlm.nih.gov/pubmed/25266407