Critics of escalating prescription prices say one of the factors driving up costs in this country is advertising. The U-S and New Zealand are the only two nations that permit drug advertising. The U-S Food and Drug Administration regulates the ads, and invited researchers to testify last week on the practical effects of the advertising. Dr. Jon Hallberg was among those who testified. He's the medical director of the primary care center at the University of Minnesota, and our regular medical and health analyst here on Minnesota Public Radio's All Things Considered. He says drug advertising certainly gets people in the clinic door.