Github is a new online service that helps programmers track and share their work. Based on "Git," a protocol for version tracking and the coordination of distributed contributions to software development, Github has become an extremely popular home for software projects both large and small, and has seen increasing use by scientists who develop software as part of their research. One notable feature of Github is its business model. There's no charge to set up an account and start posting, but there's a fee to keep your work private. This grant funds a research project by Jim Herbsleb of Carnegie Mellon's Institute for Software Research to evaluate how transparent "opt-out" development environments like Github affect the development of scientific software. Conducting case studies and analyzing archival data from Github, Herbsleb will investigate several key theses about the relationship between transparency and scientific software development, including how software developers use transparency to accomplish technical tasks, the role transparency plays in relationships between developers and the scientific community, and the difficulties transparent development environments pose for effective software development. Herbsleb's research has the potential to form the basis for policy recommendations on how transparency can be used most effectively to foster the development of scientific research.