  Stewards of social science data face a fundamental tension. On one hand, they
want to make their data accessible to as many researchers as possible to
facilitate new discoveries. At the same time, they want to restrict access to
their data as much as possible in order to protect the people represented in
the data. In this paper, we provide a case study addressing this common tension
in an uncommon setting: the Fragile Families Challenge, a scientific mass
collaboration designed to yield insights that could improve the lives of
disadvantaged children in the United States. We describe our process of threat
modeling, threat mitigation, and third-party guidance. We also describe the
ethical principles that formed the basis of our process. We are open about our
process and the trade-offs that we made in the hopes that others can improve on
what we have done.
