This document is the users' guide for Version 3.1 of the Public-Use data tapes compiled by the National Assessment of Educational Progress (NAEP), 1983-84. The Public-Use tapes are produced to allow outside researchers access to the NAEP data. The tapes accompanying this guide contain data assessing student achievement in reading and writing at grades 4, 8, and 12, and ages 9, 13, and 17, for more than 100,000 students. The data were collected from student assessment booklets, as well as teacher questionnaires, school/principal questionnaires, and a questionnaire for excluded students. The guide includes descriptions of: (1) background information on NAEP; (2) the 1983-84 reading and writing assessments; (3) the sample design, including the Balanced Incomplete Block (BIB) and Unbalanced Incomplete Block (UBIB) procedures; (4) data collection, scoring, and reporting methods; (5) issues to consider in conducting statistical analyses using this data; and (6) contents and format of the 1983-84 Public-Use data tapes and related data files and printed reports. In this version of the tapes, the maximum likelihood estimates of reading proficiency scores have been replaced with "plausible values" of reading proficiency, and writing proficiency plausible values have been added. (JGL)