The Texas Assessment of Academic Skills (TAAS) is a state-mandated, criterion-referenced or mastery test that has been administered since the 1990-91 school year. The TAAS measures student mastery of the statewide curriculum in reading and mathematics at grades 3 through 8 and at the exit level, and in writing at grades 4 and 8 and at the exit level. Although other TAAS tests are sometimes administered, the results presented and reviewed in this report are limited to the results that are included in the calculation of the State Accountability System Ratings, the aforementioned reading, mathematics, and writing tests. The report format, new this year, includes a presentation of district TAAS gains and progress toward meeting the TAAS goal and a presentation of TAAS results by grade and by disaggregated group for reading, writing, and mathematics, which includes a review of the effectiveness of prior year initiatives and strategies and recommended initiatives and strategies for the coming year. Results by objectives are not presented at the district level. Other sections of the report include a discussion of the campus improvement planning process and a summary of changes in the state accountability system for the 1998-99 school year. Campuses showed the highest gains for white students in all areas, but over all disaggregated groups, the greatest percentage of campuses made gains in mathematics. Results indicate that the strategies and initiatives that have been used to improve student achievement in mathematics have been successful, and should be continued. However, the strategies and initiatives for improving student achievement in reading and writing need to be reviewed. Seven appendixes contain a calendar of Texas Accountability System events for 1998-99, the Texas Education Agency website address, a catalogue of TAAS reports, a document on interpreting the Texas Learning Index, and some other TAAS results. (Contains 43 figures.) (SLD)