A central aim in any assessment program is to ensure fair and stable scoring from administration to administration. When administrations are decentralized, not only in location, but in frequency and in logistical configuration, it is imperative to construct training, certifying, and monitoring systems that provide continuity between the original application of scoring standards and the application of those standards from testing site to testing site and from test administration to test administration. The 1988 Tests of General Educational Development (GED Tests) include a direct measure of writing as part of the Writing Skills Test (WST). Two reliability concerns influenced the choice of methods used to incorporate an essay into the GED WST: (1) scale stability; and (2) reading reliability. Much of the GED Testing Service's research on the feasibility of including an essay focused on defining and maintaining an holistic score scale and methods of ensuring comparable reading reliability across scoring sessions and decentralized sites. Because these scores, along with those on the other four subject area tests in the battery, determine whether an examinee receives a high school equivalency credential, reliability of the WST is of major importance. Descriptions of the GED tests, the WST, and the scoring method and guide; a sample GED essay test; seven data tables; two graphs; and selected scoring formulas are appended. (Author/TJH)