For Internal Medicine it was explained to me by a Col. Downs who heads the IM dept. at Lackland. It is a point based system with points awarded in 5 areas. One of those areas is military service so if you have time in or come from a military program you are more likely to get a spot. However, I know for certain that a civilian can match with the AF in IM. I did match this past year with the AF. I turned down the offer though as seems to be a general mood of the board found out: the recruiter was not completely honest with information. This comes from speaking to the doctors once I got into the interview phase who were much more open and honest with me. They do have a retention problem and the only person I spoke with who knew for certain he would stay was the Col. Everyone else was either getting out or seriously considering. That was a huge red flag in my mind. Which is unfortunate as I was very impressed with every physician I spoke to while at Lackland and Keesler.