Colorado students did worse this year on the test known as “the nation’s report card” than they did the last time it was administered two years ago, according to data released Wednesday. But the state’s scores are still better than national averages.

The National Assessment of Educational Progress, or NAEP, is a set of reading and math tests given every two years to a sample of fourth and eighth graders in each state. Earlier this year, 4,500 Colorado students spent one hour each taking one of the tests.

On the fourth-grade math tests, 43 percent of Colorado students scored proficient or better, down from 50 percent in 2013. On the eighth-grade math tests, 37 percent of students scored proficient or better, down from 42 percent two years ago.

On the fourth-grade reading tests, 39 percent of students scored proficient or better, down from 41 percent in 2013. On the eighth-grade reading tests, 38 percent of students scored proficient or better, down from 40 percent two years ago.

Most national scores, with the exception of fourth-grade reading, dipped as well but the declines weren’t as steep. However, Colorado education officials said the decreasing scores aren’t cause for concern.

“If we start seeing declines over a period of time — if we see scores dip again in 2017 — it becomes a little more alarming,” said Will Morton, director of assessment administration for the Colorado Department of Education. “Right now, with a single-year dip, I wouldn’t be too concerned about it yet.”

HOW DO COLORADO’s 2015 SCORES COMPARE TO NATIONAL SCORES?

U.S. students have taken the NAEP exams since the early 1990s in an effort to provide a consistent measure of student performance at a time when states’ standards varied widely.

Many states have adopted or are developing new tests that reflect shared standards, potentially allowing for more detailed and frequent comparisons of students across the country. But the NAEP tests are not officially aligned with the standards adopted by Colorado and more than 40 other states. Called the Common Core standards, they detail what students should know in reading and math.

By the 2013-2014 school year, the Common Core standards were in effect in all Colorado schools. The state also rolled out new tests that align with them. Students took the reading and math tests, known as PARCC, for the first time last spring.  The state is scheduled to release the results in November.

“When we look at tests as a measurement for student success — and they’re only one way to measure student success — those tests, which are taken by all students … are what we really look at,” said Dana Smith, interim chief communications officer for CDE.

HOW HAVE MATH SCORES CHANGED OVER 10 YEARS?

But officials said NAEP serves a purpose, too, in that it provides a glimpse into how Colorado students are performing compared to students across the country. Colorado ranks in the middle: Its scores were 23rd highest in fourth-grade math, 17th highest in eighth-grade math, 23rd highest in fourth-grade reading and 18th highest in eighth-grade reading.

“Overall, we’re about where we would expect to be,” Morton said, adding that “if you look at it on a bell curve, we’re in the middle of that bell curve toward the higher end.”

Colorado’s scores have generally improved over the years, while achievement gaps between white and minority students and low-income and non-low-income students have stayed the same. This year, Colorado’s scores did not improve. Morton and Smith were hesitant to speculate as to why, but they noted the differences between NAEP and the Common Core.

NAEP may not be testing what students are learning in their classrooms, they said. A recent study by the American Institutes for Research found that the similarity between the NAEP math tests and the Common Core is “reasonable,” but there are gaps. For example, the study said it appears that “a notable amount” of middle-school math content recommended by the Common Core is not part of the NAEP test.

“As our teachers continue to teach to our Colorado standards,” Morton said, “those differences between what NAEP is designed to test versus what our teachers are being asked to teach — those differences may be highlighted.” But it’s too early to tell for sure, he said.

“Until we have more years of implementation, we can’t really tell if this is an implementation dip or a fundamental difference between our standards and the blueprint of the NAEP test,” Morton said.

HOW HAVE READING SCORES CHANGED OVER 10 YEARS?

NAEP officials took a similar view of the scores, which stayed stagnant or declined in most states.

“One downturn does not a trend make,” said Peggy Carr, the acting commissioner of the National Center for Education Statistics, which administers the NAEP tests.

“It’s not a multi-year trend we’re seeing,” added Bill Bushaw, the executive director of the National Assessment Governing Board, which sets the framework for the NAEP tests. He referenced “curricular uncertainty” in American classrooms and said experts have suggested that “slight declines” often precede improvements.

The NAEP tests are not meant to be tied to a specific curriculum, Bushaw said. However, he predicted that the national board would take another look at the framework in light of this year’s scores and reports such as the one from the American Institutes for Research.

In Colorado, officials said that while NAEP is helpful, it’s just one piece of the overall testing puzzle — and one that’s based on a small sampling of the state’s nearly 900,000 students.

“We don’t get too upset when we see small gains or losses,” Morton said.

Chalkbeat Tennessee reporter Grace Tatter contributed information to this report.

Data source: National Assessment of Educational Progress 

Graphics by: Sarah Glen/Chalkbeat