Hundreds of thousands of dollars in debt, and no residency. That's the situation for 412 medical school graduates this year in the United States, including a few in Pittsburgh. A residency -- paid, on-the-job training -- is an essential step in becoming a medical doctor. In some cases, students' failure to obtain a residency has nothing to do with their performance, but rather with the supply and demand of the system that allocates them, the National Resident Match Program. It also has to do with simple math. The National Resident Match Program's annual report released earlier this month shows 26,678 positions. For the second year in a row, the number of graduates exceeded the number of residencies available.