The 2018 Nebraska Student-Centered Assessment System (NSCAS) Summative technical report documents the processes and procedures implemented to support the Spring 2018 NSCAS Summative English Language Arts (ELA), Mathematics, and Science assessments by NWEA under the supervision of the Nebraska Department of Education (NDE). The technical report shows how the processes, methods applied, and results relate to the issues of validity and reliability and to the "Standards for Educational and Psychological Testing" (AERA, APA, & NCME, 2014). The following sections are presented: (1) Introduction; (2) Test Design and Development; (3) Test Administration and Security; (4) Scoring and Reporting; (5) Psychometric Analyses; (6) Standard Setting; (7) Test Results; (8) Reliability; and (9) Validity.