For decades, the Wake County Public School System — the nation’s 18th largest — has been known as a strong academic district committed to integration.

From the 1970s to the 1990s, that meant racial integration.

In 2000, after courts ruled against using race-based criteria, Wake became one of the first districts in the nation to adopt a system of socioeconomic integration. The idea was that every school in the county (163 at present) would have a mix of children from poor to rich. The target for schools was a 60-40 mix — 60 percent of students who did not require subsidized lunches and 40 percent who did.

Then in 2009, a new conservative majority was elected to the Wake school board, and last spring it voted to dismantle the integration plan. Instead, families would be assigned to a school nearer their neighborhood. This meant a child who lived in a poor, black section of Raleigh would be more likely to go to a school full of poor black children, and a child living in a white, upper-middle-class suburb would be more likely go to a school full of upper-middle-class white children.

In most places that would have been it. Not here. This is a well-educated labor force (50 percent of employees are college graduates) that works in the high-tech Research Triangle and is predisposed to finding new ways to solve complex problems.

And that’s just what they set out to do. Two weeks ago, civic leaders here unveiled their proposal for a third generation of integration: integration by achievement. Under this plan, no school would have an overwhelming number of failing students. Instead a school might have a 70-30 mix — 70 percent of students who have scored proficient on state tests and 30 percent who are below grade level.