Texas students have made extraordinarily large gains on statewide achievement tests, the Texas Assessment of Academic Skills (TAAS), gains so dramatic that they have been dubbed the "Texas miracle." There is general agreement that these gains are attributable to the high stakes accountability system in Texas, but there is some question about what they really mean. Several analyses were conducted to examine whether TAAS scores can be trusted to provide an accurate index of student skills and abilities. Scores on the National Assessment of Educational Progress (NAEP) were used to determine how much students in Texas have improved and whether this improvement is consistent with what has occurred nationwide. Whether gains in TAAS scores between 1994 and 1998 were comparable to those on the NAEP was studied. Also measured was whether differences in scores between whites and students of color on the TAAS were consistent with the difference between these groups on the NAEP. Finally, whether TAAS scores were related to scores on three other tests given to students in 20 Texas elementary schools was studied. Findings from these analyses raise serious questions about the validity of gains in TAAS scores. The main finding is that average test score gains on the NAEP in Texas exceeded those of the nation in only one of three comparisons. The results illustrate the difficulties in relying on statewide test results as the sole measure of student achievement when these scores are used to make high stakes decisions about teachers and schools, as well as student. (Contains 27 references.) (SLD)