Utah's achievement gap appears to be narrowing in some areas, but not in others, since No Child Left Behind took effect in 2002.

A report issued Tuesday by the Center on Education Policy shows the gap between low-income and more well-off students narrowed in reading and math. Reading gaps between Hispanics and whites also narrowed in elementary, middle and high school grades examined.

But when you look at Utah's performance based on average test scores — called effect size — rather than the percent of students scoring as proficient, the gap between Hispanics and whites actually widened in reading across all grades analyzed.

And the gap between the relatively few black students in Utah and the overwhelming Caucasian majority is widening no matter how you look at it.

"It's encouraging news, and it's discouraging news," Mark Peterson, spokesman for the Utah State Office of Education, said of the report. "We're headed in the right direction but not nearly fast enough."

Utah students overall are raising their achievement levels on reading and math tests used for No Child Left Behind. Utah's proficiency rates generally range between 77 percent and 80 percent in reading and 68 percent to 81 percent in math. Those numbers represent up to a 6 percentage point gain.

But a look at student groups shows a different story. Black students slipped more than 5 percentage points to 60 percent proficient in reading, putting them 24.4 percentage points behind whites, whose scores rose nearly 4 percentage points. In math, the gap between blacks and whites increased by 6.5 percentage points to more than 27.

The study notes that blacks make up approximately 1 percent of test takers, so results from the small sample should be read with caution.

When analyzed in terms of effect size, which use average test scores to gauge student performance over time, the gap in reading widened between Hispanics and whites, by 0.22 standard deviation points. So while more Hispanic students might achieve levels considered proficient by the state, their actual test scores are not keeping pace with growth shown by white students.

Hispanics make up between about 12 percent and 15 percent of the test-takers.

"I would pay a great deal of attention to the effect size, because that's the clear data on increases in test scores," Center on Education Policy President Jack Jennings said. The mixed showing is "a common problem throughout the country and shows that if we're sincere about closing the gaps, we're going to have to do much more than what we're doing."

Peterson said the increased gap in average test scores might be in part due to an influx of new Hispanic students. Some may be immigrants who are learning English as a second language, trend data indicates.