Nearly a quarter of all office-based physicians require pharmaceutical or medical device sales reps to make an appointment, according to a SK&A Information Services study.

The study found a direct correlation between the number of physicians in an office and appointment requirements. For example, in offices with 10 doctors or more, 40.02% of the 230,000 medical practices surveyed require an appointment. The medical practices represent 640,000 physicians, according to the study, which surveyed physicians’ offices by telephone. Seventeen percent of all physicians surveyed refuse to see sales reps at any time.

In other data, Minnesota, Montana and Washington were the most hostile to sales reps, with 35.56% of the physicians surveyed in Minnesota reporting that they will not see reps at all, followed by 32.91% in Montana, and 32.67% in Washington, according to the study. The states most open to sales reps–Louisiana, Kentucky and Mississippi–won’t see reps 16.35%, 16.33% and 15.85% of the time, respectively.

Pediatric Hematology/Oncology physicians are most ardent about appointments, requiring them at a rate of 66.61%. Neuroradiology specialists, pathologists and diagnostic radiologists offered the most limited access for reps; the three groups decline visits at an average rate of 91.24%, according to the study. Allergists/Immunologists, dermatologists and gastroenterologists were the three groups most likely to see sales reps.