I am a medicine attending who has the opportunity to work with many students during their third year of medical school. My personal feeling is that the medicine rotation should not be done first or last but rather sometime in between. Having said this, there are many who favor taking medicine first. Why? Because once you have taken medicine and gotten comfortable performing H&Ps, presenting patients, and doing write-ups, it is easier to take these skills that you have acquired and adapt them to your other rotations. The reason I do not advise students to take medicine first is because the start of the third year of medical school is difficult for most students. The world of clinical medicine is very different than the first two years of medical school and students are often overwhelmed by their new clinical responsibilities. This anxiety coupled with inexperience often leads to students not performing at the level they are capable of, a level which they achieve with subsequent rotations. In a perfect world, attendings would take this inexperience into account and adjust their expectations accordingly but I can tell you that this does not often occur.
As for doing medicine last, my feeling is that this is also to your disadvantage. As I mentioned above, the skills that you acquire can serve you well on your other rotations. In addition, some of your other rotations will expose you to topics that you would already have seen in medicine. And your question about high expectations is a good one. Right or wrong, many attendings do expect more from their third years at the end of the year. So mistakes that may have been more easily tolerated at the beginning of the third year may leave an attending shaking his head, saying "I'm surprised that this student hasn't learned this by now".
These are just my opinions and to my knowledge, there is no data that says students who do medicine first, last, or sometime in between are better doctors than their counterparts. Hopefully that helps but if you have any other questions, please feel free to send me a PM.
Samir Desai
Assistant Professor of Medicine
Baylor College of Medicine