GPS Disruptions: Efforts to Assess Risks to Critical Infrastructure and Coordinate Agency Actions Should Be Enhanced

A letter report issued by the Government Accountability Office with an abstract that begins "To assess the risks and potential effects from disruptions in the Global Positioning System (GPS) on critical infrastructure, the Department of Homeland Security (DHS) published the GPS National Risk Estimate (NRE) in 2012. In doing so, DHS conducted a scenario-based risk assessment for four critical infrastructure sectors using subject matter experts from inside and outside of government. Risk assessments involve complex analysis, and conducting a risk assessment across multiple sectors with many unknowns and little data is challenging. DHS's risk management guidance can be used to help address such challenges. However, we found the NRE lacks key characteristics of risk assessments outlined in DHS's risk management guidance and, as a result, is incomplete and has limited usefulness to inform mitigation planning, priorities, and resource allocation. A plan to collect and assess additional data and subsequent efforts to ensure that the risk assessment is consistent with DHS guidance would contribute to more effective GPS risk management.