"Benchmarking for Success: Ensuring U.S. Students Receive a World-Class Education", is a report by the National Governors Association, the Council of Chief State School Officers, and Achieve, Inc. It is the report the US federal government is using to justify the need for the Common Core. You can find the actual document here. Page nine is the beginning of the explanation of how the US is lagging compared to the rest of the world.
Christopher Tienken, Ed.D is an assistant professor of Education
Administration at Seton Hall University. In this 22 minute video he explains how the information in the Benchmarking Report is not based on real data, and illustrates how Common Core lacks real scientific evidence for its very existence. Please note that at 19:30 Tienken does start to move away from providing hard data to refute the need for Common Core, into proselytizing.