A recent Abell Foundation study has confirmed what educators have long known: That where a student lives has at least as big an impact on academic achievement as such factors as family income, class size and per pupil spending. In fact, attending a school where most of one's classmates aren't poor is one of the best predictors of school success: Even poor students who attend such schools score better on standardized tests than their peers in schools with high concentrations of poverty.

Given the strong correlation between where students live and how well they do in school, the foundation says, Baltimore City could help thousands of youngsters improve their chances of getting a good education simply by subsidizing their families' move to the suburbs.

This idea is hardly new, and for a variety of reasons the state's political and educational leaders have mostly ignored it. But the findings still hold valuable lessons for Baltimore City and its surrounding counties.

The Abell report focused on students in Montgomery County, one of the state's richest subdivisions but one that also houses a growing number of low-income, minority families.

Researchers compared the academic achievement of low-income students enrolled in county schools where most of their peers were poor with that of similar students in schools where most of their classmates were middle-class.

What they found was that poor children in the mostly middle-class schools achieved more and learned faster than their peers in schools with high concentrations of poverty. Not only did those students narrow the so-called "achievement gap" between rich and poor more quickly, they did so despite the extra funding and resources the high-poverty schools received to compensate for the disparity in family incomes.

How, you might ask, was such an experiment even possible, given that housing costs in Montgomery County are far beyond the means of most poor families?

The answer is that — unlike most other Maryland jurisdictions — Montgomery County has long had a policy of subsidizing affordable housing for low-income families and integrating them into existing communities. And it does so in such a way that the relatively few low-income families scattered throughout otherwise affluent neighborhoods have had virtually no impact on the character, quality of life or safety of those communities. Essentially, Montgomery treats low-income housing as a function of zoning policy — builders have an incentive to include affordable units in their developments, and the county's housing authority gets first dibs on them.

Such a policy would have limited effectiveness in Baltimore City, both because the opportunities for new development are limited and because the city lacks a sufficient number of middle-class communities where low-income families could be relocated without altering the character of the neighborhood. In order for such a scheme to work in Baltimore, the problem would have to be tackled on a regional basis so that low-income families would have to have the option of relocating to middle-class communities in the suburbs.

Such a remedy was proposed in a now 15-year-old discrimination suit against the Baltimore City Housing Department brought by the American Civil Liberties Union on behalf of public housing residents. The residents charged the department with intentionally discriminating against African-American residents by limiting their housing subsidies to poor black neighborhoods in the inner city. The case is still awaiting a final resolution in the courts, but in the intervening years only about 1,800 families have been awarded housing certificates that would enable them to relocate outside the city.

If the courts so far have been unable to impose a solution, there's still nothing stopping city and county officials from adopting a regional plan to create more subsidized housing units along the lines of Montgomery County's effort. The creative use of housing subsidies to create better educational opportunities for all the regions' children may sound idealistic and impractical, but the Abell foundation suggests that it's not only feasible but affordable; the average cost per child would only be about $6,000 per year. That's not a big investment given the undeniable importance of a well-educated workforce for Maryland's future.

But as a practical matter there is little incentive for them to do so. City leaders are leery of any scheme that might accelerate Baltimore's long-running population decline; they also fear antagonizing suburban officials, who worry that an influx of low-income city families will increase pressure on already limited stocks of affordable housing. And the idea has been political anathema in the suburbs, where voters have traditionally rejected it.

Even if local leaders remain unwilling to embrace a regional approach to housing policy — at least absent a federal court order forcing them to do so — suburban leaders do have a good reason to adopt something similar to Montgomery's policy. Poverty is not limited to the city, and the suburban counties have a strong interest in making sure that it doesn't become concentrated in any one community or lead to the emergence of the kind of high-poverty schools that depress student achievement. There's no question the counties need more affordable housing, if only because it would make it easier for vital employees, such as teachers, police and firefighters, to live closer to where they work.

Montgomery County's concept of allowing developers to build with more density than zoning rules would typically allow in exchange for a community benefit isn't foreign to this region. Baltimore County, for example, allows something similar through the planned unit development process. But there, the standards for what constitutes a "community benefit" are far too vague and subjective. Explicitly linking the zoning tool to affordable housing policy would gradually increase the supply of such units without altering the character of already existing neighborhoods.

Such a step wouldn't address the concentration of poverty in the city, but it could create the conditions in which the eventual adoption of a regional approach to affordable housing could be feasible. The objections to the ill-fated Move to Opportunity program of the 1990s were rooted in the suspicion that the poor would be concentrated in certain neighborhoods but held out from others. A well run program modeled after Montgomery County's could eventually allay that fear.