As world research capacity expands rapidly, the United States science and engineering enterprise finds itself in a new position. Decades of U.S. dominance in science and engineering research helped create U.S. leadership in emerging industries such as information and biotechnology. But U.S. science and engineering research are likely in coming decades to take their place among many strong players on a global scene. Europe, Japan and Korea are already international powers in research and development, and China, India, Brazil, and South Africa are rapidly expanding their capabilities. Under these circumstances, the capacity to monitor the world research front and absorb research knowledge from other countries is more important than ever for the United States. Innovation in the U.S. will thrive best in an open information environment in which our ties to the rest of world research and development are strong. Many factors will contribute to the absorptive capacity of U.S. research. International collaboration is certainly one. This project explores the benefits of international collaboration for U.S. researchers and their collaborators. Several models for international collaboration exist, including informal versus formal and small versus big science. In order to take a close look at the benefits of collaboration under these models, this study focuses on two fields, bio-fuels and materials science. To compare informal with formal models, an examination is done of each area before and after a formal policy intervention in 2007 that encourages international collaboration (in bio-fuels the U.S.-Brazil ethanol agreement and in materials science the start of the user program at the Spallation Neutron Source). In addition, these examples allow examination of both a small science area and a big science project in the periods before and after a formal collaboration program starts.