International collaboration in science and technology (S&T) research has risen over the past 15 years from approximately 25 percent to over 35 percent, according to Knowledge, Networks and Nations: Global Scientific Collaboration in the 21st Century — a new report from the Royal Society Science Policy Center. The special advisory group established by the Royal Society analyzed data that include research articles in international journals, citations in those articles, national rates of patent registration, number of researchers per nation, national expenditures on research and development (R&D) and the impacts of S&T research. Data was collected using several methods and sources including a call for evidence, data mining and face-to-face and telephone interviews.