When discussing the risk of introducing drones into the National Airspace System, it is necessary to consider the increase in risk to people in manned aircraft and on the ground as well as the various ways in which this new technology may reduce risk and save lives, sometimes in ways that cannot readily be accounted for with current safety assessment processes. The Committee on Assessing the Risks of Unmanned Aircraft Systems (UAS) Integration examined the various ways that risk can be defined and applied to integrating UAS into the National Airspace System managed by the Federal Aviation Administration (FAA). The committee looked at recent developments in this field and consulted numerous experts in academia, industry, and government. The committee developed 11 recommendations that are presented in this report.