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The most critical aspect is of course preventing such a scenario entirely. This needs to happen at the selection of the proposal, the selection of the mentor, and the selection of student. A proposal of proper scope, a dedicated mentor, and a student with a visible history of seeing projects to their end is critical to success. Also critical is observing their involvement in the community up prior to the student selection process. Finally a proper interview is probably required in order to find out whether the mentor/student pairing is ideal and whether the student will be free of time conflicts during the GSoC time period to see their project to completion.
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