1- The authors did not mention how long they waited before they classified the physician as a non responder. Also, no information is given on the time between the first mailing to the telephone follow-up and the two additional mailings.
2- Physicians' (I assume it's plural) awareness of any policy that limited their access to pharmaceutical representatives was mentioned in the methodology but not measured.
3- This study is a very good study and I have confidence in the results.
4- No clear information is (or was) given about why the authors chose the cost of a complete course of antibiotic therapy or a 30-day supply of the antihypertensive agent as a reference.