Goodman Research Group, Inc. (GRG) is serving as the external evaluator of the NSF-funded Science Festival Alliance (SFA), a collaborative started by the University of California San Diego, the MIT Museum (Cambridge), the University of California San Francisco, and The Franklin Institute (Philadelphia). The early focus of the SFA has been on helping establish and sustain science festivals in each of these four cities. The Alliance’s long-term goal is to facilitate the creation of a growing network of festivals and a community of science festival practitioners. This report focuses on the knowledge gained about the project’s impacts during the first and second years of project operations and evaluation. It describes the results of surveys of ISE professionals served by the SFA. It also describes the results of surveys of festival attendees and festival partners participating in the San Diego, Cambridge, Philadelphia, and Bay Area Science Festivals. The SFA currently supports over two-dozen science festival initiatives across the country, and SFA evaluation findings have significant implications for these many initiatives.