So what happens when you get into both an MD school and a DO school? According to data from AACOM, of applicants who applied to both DO and MD schools in 2010 who were admitted to at least one MD school, 89% chose to enroll in that MD school (only 9% of that group chose to enroll at a DO school). In other words, when you have the choice of both, most pre-meds choose the MD school.
As a result, about 20% of students who apply to DO schools end up matriculating at an MD school, thus distorting our data. In reality, MD schools are harder to get into. Indeed, their average GPA's and MCAT scores suggest as much:average MCAT average GPA
According to that same report, of all applicants who applied to DO schools, 55% received an offer of admission. Though we don't have the corresponding number for MD applicants, we can compare the 55% acceptance rate to DO schools to a "true" acceptance rate to MD schools of a hair over the 43% national number.
So what does this all mean to your application?
1. It shows why DO schools are concerned with losing applicants to MD schools. They're concerned, because it happens quite a bit. Roughly half of applicants to DO schools are applying to MD schools, and when they get into both, they mostly choose the MD school. As a result, I believe a successful application to DO schools will include a specific reason you prefer getting a DO over getting an MD degree.
Be sure to include this argument in your personal statement to DO schools, and be prepared to answer the same question "why DO?" when you go into your interview at a DO school.
2. If your numbers aren't great, apply to DO schools as well as MD schools.
DO's end up in all kinds of specialties (not just primary care), so you will have plenty of options open to you at both schools.
3. The market seems to have spoken, however, and students still prefer MD over DO schools. There may be many reasons for this choice. To name a few: MD schools are better known, have better research opportunities, and have better options of getting students into the more competitive specialties. Whatever the reasons for the choice, the preference exists, and when figuring out where to apply, decided whether what you want from your career is a good fit for MD, DO, or both.