I'm amused that only 50% of applicants actually finish their secondary. Hell, I barely completed it myself! I wonder if their yield (the % of accepted applicants who choose to matriculate) is greater than other schools. I would also be interested to see the averages for GPA and MCAT for the two groups (submitted w/o secondary and submitted w/ secondary) to see whether or not Duke actually loses a chance at recruiting many high quality students.
Though I am sure Duke believes its reasons are sound, I doubt they fully understand how their secondary pushes away students who must prioritize their time between the dozen or more applications they must fill out in an already packed schedule. If I were only applying to Duke and a few other schools, I would have been happy to spend the 7+ hours writing and editing their secondary essays, but the reality of medical school admissions is that most of us must apply to a great number of schools who also require their own essays. The average applicant applies to ~14 schools. If each school required personal essays like Duke's, the secondary process would require nearly 100 hours to complete given a conservative estimate of seven hours per application. Duke's requirements may allow the admissions office a clearer look into the personal qualities of its applicants, but in the process it makes the school seem pretentious and either apathetic or disconnected from the stresses of its students.