Summary:
ZIP code 94521 has two public high schools, both serving grades 9–12: Clayton Valley Charter High and Concord High. The fairest comparison is their 2024–2025 all-grades test results, the latest year available for both schools. The clearest difference is academic proficiency: Clayton Valley Charter led Concord in ELA, math, and science.
Clayton Valley Charter stands out at the top of the two-school comparison, while Concord had the lower results in all three subjects. Clayton scored 70% in ELA, 37% in math, and 37% in science, compared with Concord’s 43%, 17%, and 17%—gaps of 27, 20, and 20 percentage points. Clayton was above the state in ELA and science and essentially at the state level in math; Concord was below the state in all three subjects. SchoolDigger’s 2024–2025 ratings also favored Clayton: 491st of 2,162 schools, at the 77th percentile with four stars, versus Concord’s 1,340th, at the 38th percentile with two stars.
Concord’s available test results declined in ELA by 3 percentage points and were essentially flat in math from 2024–2025 to 2025–2026, while science rose by 3 points; because state scores improved in all three subjects, Concord’s gaps below the state widened by 4 points in ELA and 1 point each in math and science. Its SchoolDigger percentile also fell from 45 to 33 across three reported years, while Clayton’s rose to 88 and then slipped to 77. Other differences provide context, not explanations: in 2024–2025 Clayton had 2,373 students and a 25.1 student-teacher ratio, compared with Concord’s 1,137 students and 19.5 ratio; free/reduced lunch eligible figures that year were 22% and 70%, respectively. Concord’s 2025–2026 graduation rate was 98% versus 88% statewide, but its chronic absenteeism was 23% versus 18% statewide. One limitation is that Clayton’s later test results are not available here, so the year-over-year pattern cannot be compared across both schools.
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