Achievement tests are used to make high-stakes (e.g., special education placement) decisions, and previous research on norm-referenced assessment suggests that errors are ubiquitous. In our study of 42 teacher trainees, utilizing five of the six core subtests of the Kaufman Test of Educational Achievement, Third Edition (KTEA-3), we found that while most trainees make errors, they do not make a large number per person with the exception of a few error-prone trainees. In addition, Wilcoxon signed-rank tests indicated that reading comprehension was the most prone subtest to administration (T = 120; p < 0.001) and clerical (T = 45; p < 0.01) errors. However, subtests pairwise comparisons indicated nonsignificant differences between error rates across subtests. Based on these findings, we recommend that training programs focus extra attention on reading comprehension and remediating students who make a disproportionate number of errors. Implications for future research are also noted.