; (C) a description of best practices grounded in principles of scientific research for how such safety will be achieved; and (D) an assurance that the eligible entity will report outcomes of such project to track effectiveness based on standardized criteria established by the Office of Civic Bridgebuilding under subsection (b)(1). (4) Uses of funds An eligible entity receiving a grant under this subsection shall use the grant funds to carry out a project to advance civic bridgebuilding in communities across the United States. (e) Comptroller General The Comptroller General of the United States shall, not later than 18 months after the end of the 3-year period of the program carried out under subsection (d)(1)(A) and, as applicable, not later than 18 months after each 3-year period of the program carried out under subsection (d)(1)(B), submit to Congress a report, which summarizes and assesses the effectiveness and impact of the activities carried out under grants awarded under subsection (d). (f) Definitions In this section: (1) Civic bridgebuilding The term civic bridgebuilding — (A) means an activity, grounded in principles of scientific research, that— (i) fosters respect between diverse communities; (ii) supports social cohesion and diminishes polarization; (iii) forges a sense of common civic purpose; and (iv) seeks to address a public concern such as unmet human, educational, health care, environmental, or public safety needs; and (B) includes— (i) activities that take place in local communities, where individuals and institutions come together to build empathy and social cohesion, strengthen belonging, and address local issues; and (ii) activities at the field level, where civic bridgebuilding leaders work together to share research and best practices, learn from one another, and grow other civic bridgebuilding. (2) Civic bridgebuilding field The term civic bridgebuilding field means— (A) the programs, leaders, and community groups involved in civic bridgebuilding activities