But Unz also plays with statistics to build his case, saying, for example, that a gain from the 10th percentile to the 25th percentile represents a 150 percent increase. In fact, the actual improvement in scores is less dramatic. To score at the 10th percentile in second-grade reading, for example, students must answer 43 of 118 questions correctly. To score at the 25th percentile, they need 57 right. In other words, a 33 percent increase in the number of correct answers yields a 150 percent gain in percentile points.
Most educators take a more cautious approach to test gains.
Scores often rise in the second year of a test as students and teachers become more familiar with the format and content. Better teacher training, new textbooks and class-size reduction could also boost scores. Measures other than test scores raise questions about English immersion. The rate of students being reclassified from limited English to fluent English declined this year in Westminster, Magnolia and Orange Unified, which pioneered English-only instruction. Othmer said banning Spanish instruction hurts newcomers, who need help understanding the most basic vocabulary.