This document reports on work done by the Institute for Defense Analyses (IDA) for the Office of the Program Manager, Information Sharing Environment (PM-ISE), Office of the Director of National Intelligence and Deputy Chief Information Officer (DCIO) and for the Command, Control, Communications, and Computers and Information Infrastructure Capabilities (C4&IIC), Department of Defense (DoD) Chief Information Officer (CIO). The objective of this project is to assess the current state of communications interoperability between DoD Public Safety and Emergency Management (PS/EM) entities and United States (US) civilian PS/EM entities and how that is likely to change as the next generation of public safety information systems is implemented across the nation. This white paper addresses the data reuqirements for information exchanges involving DoD and US civilian PS/EM entities. IDA’s investigations have identified a set of data standards that need to be considered for use in future DoD and US civilian PS/EM communications systems, such as FirstNet. IDA will use these standards in developing a semantic model (an ontology) of core PS/EM communications data requirements to facilitate semantic interoperability and enable automated reasoning with such data.