Safe Schools Improvement Act of 2018 This bill amends the Elementary and Secondary Education Act of 1965 to require states to direct their local educational agencies (LEAs) to establish policies that prevent and prohibit conduct, including bullying and harassment, that is sufficiently severe, persistent, or pervasive to: (1) limit students' ability to participate in, or benefit from, school programs; or (2) create a hostile or abusive educational environment that adversely affects students' education. LEAs shall also provide: (1) students, parents, and educational professionals with annual notice of the conduct prohibited in their disciplinary policies; (2) students and parents with grievance procedures that target such conduct; and (3) the public with annual data on the incidence and frequency of that conduct at the school and LEA level. The Department of Education must conduct, and report on, an independent biennial evaluation of programs and policies to combat bullying and harassment in elementary and secondary schools. The National Center for Education Statistics shall collect state data to determine the incidence and frequency of the conduct prohibited by LEA disciplinary policies.