Against the recommendation of its staff and of the San Jose Unified School District, the Santa Clara County Board of Education has renewed the charter of a struggling charter school, Sunrise Middle.

The board voted 5-2 last week to extend the charter for five years, with Trustees Anna Song and Darcie Green dissenting.

San Jose Unified had declined to renew the charter of the 2½-year-old school, which focuses on low-income students who are performing below grade level.

The County Office of Education staff agreed, and expressed concerns about a lack of rigor in the curriculum the school's budget assumptions. Last year Sunrise scored 648 on the state's Academic Performance Index, placing it in the bottom 10 percent of California schools and below other San Jose Unified middle schools.

School Director Teresa Robinson noted that Sunrise's score represented a gain of 75 points from the previous year and that the school had met all its annual growth targets. She also wrote the board that the school has high attendance rates and high parent-satisfaction ratings. She said the school plans to overhaul its math education and offer two hours of math daily.