This manual was written to provide technical information regarding the General Educational Development (GED®) test as evidence that the GED® test is technically sound. Throughout this manual, documentation is provided regarding the development of the GED® test and data collection activities, as well as evidence of reliability and validity. This manual is made up of 10 chapters: (1) Introduction to the GED® tests and an overview of the GED® testing program, including the purposes of the tests and proper uses of test scores; (2) The underlying theory of action for the GED® testing program and the framework for assessing validity; (3) The GED® test specifications and process for developing forms; (4) The standardization process, including the norming, scaling, and equating processes; (5) The standard-setting process for both the High School Passing Standard and GED® with Honors; (6) Scoring processes for both machine- and human-scored test items; (7) The reliability of GED® test scores; (8) Accumulated evidence to support the validity argument; (9) Various accommodations for test-takers with disabilities; and (10) Supplemental materials for test preparation. This manual was written for anyone who is interested in (1) learning about the background of the GED® testing program, (2) understanding how the GED® test was developed and scored, (3) comprehending the statistical characteristics of the GED® test, or (4) knowing more, in general, about the GED® testing program. The following are appended: (1) Reasoning through Language Arts Scoring Rubric; and (2) Social Studies Scoring Rubric.