Cherokee, Forsyth and Fayette counties continue to be among the metro area's top performers when students' skills in math and four other subjects are checked on the high-stakes Criterion-Referenced Competency Tests, new data released Wednesday shows.

Students in the city school systems of Decatur and Buford also made strong showings on the CRCTs, while the school systems in DeKalb, Clayton and Atlanta had some of area's the lowest passing rates.

Results of the tests of students' knowledge of reading, English/language arts, science, social studies and math are closely watched since they help determine whether a school makes Adequately Yearly Progress, a critical benchmark of the federal No Child Left Behind Act.

Students also have to pass five of the tests -- reading for third-, fifth- and eighth-graders and math for fifth- and eighth-graders -- to automatically be promoted to the next grade.

This year, first- and second-graders didn't take the test as a cost-saving measure. But 758,512 Georgia students in grades 3 through 8 did, and they showed slight improvement over 2010 test-takers.

Among eighth-graders who must pass the math portion of the CRCT to automatically be promoted to ninth grade, the statewide passing rate was 77.7 percent.

In the metro area,  the passing rate was 65.9 percent for Atlanta Public Schools, 68.3 percent for Clayton and 65.8 percent for DeKalb.

In comparison, the passing rate on that same test was 89.6 percent in Cherokee County, 93.4 percent in Fayette County, 86.8 percent in Buford and 94.6 percent in Decatur.

Forsyth County, an affluent north Atlanta suburb and traditionally a top test performer, had a 96.9 percent passing rate on the eighth-grade math test, the best reported in the state.