Waterford — The school district’s students this year recorded the highest scores in the history of the public school system on state standardized tests, according to a Board of Education presentation by the assistant superintendent of schools Thursday.

Assistant Superintendent Craig Powers said there were record improvements across all subject areas on the Connecticut Academic Performance Test — administered annually to 10th graders — with the exception of science, which had higher scores in 2008.

Elementary- and middle-school students in grades 3 through 8, who annually take the Connecticut Mastery Test, also showed improvement.

Last year’s 10th-grade class placed first in reading, second in science, fourth in writing and sixth in mathematics among its District Reference Group on the Connecticut Academic Performance Test. Waterford is one of 24 school districts in its DRG, which groups districts by size and wealth, among other things, and includes East Lyme, Stonington, Old Saybrook, Ledyard and Colchester.

“Adding literacy support at the high school, adding over time the reading workshop and writing lab as support mechanisms, we’re really showing that we have a good level of achievement,” Powers said.

Improvements in reading, science, writing and math were slight, with the largest percentage-point improvement coming in science, where 93.7 percent of 10th-graders tested at or above the federal proficiency level, an increase of 3.6 percentage points over last year.

— Julianne Hanckel