An expert work group with 7 members was formed under the cosponsorship of 5 U.S. federal agencies to identify common data elements for research related to posttraumatic stress disorder (PTSD). The work group reviewed both previous and contemporary measurement standardization efforts for PTSD research and engaged in a series of electronic and live discussions to address a set of predefined aims. Eight construct domains relevant to PTSD were identified: (1) traditional demographics, (2) exposure to stressors and trauma, (3) potential stress moderators, (4) trauma assessment, (5) PTSD screening, (6) PTSD symptoms and diagnosis, (7) PTSD-related functioning and disability, and (8) mental health history. Measures assigned to the core data elements category have relatively low time-and-effort costs in order to make them potentially applicable across a wide range of studies for which PTSD is a relevant condition. Measures assigned to the supplemental data elements category have greater costs but generally demonstrate stronger psychometric performance and provide more extensive information. Accordingly, measures designated as supplemental are recommended instead of or in addition to corresponding core measures whenever resources and study design allow. The work group offered 4 caveats that highlight potential limitations and emphasize the voluntary nature of standardization for PTSD-related measurement.