A story in the New York Times reports on a study released by a Washington think tank. The study is the work of economists, who calculate that closing the achievement gap and raising up everyone’s test scores, would have a dramatic effect on the economy.


If Americans were able to match the scores reached in Canada, which ranks seventh on the O.E.C.D. scale, the United States’ gross domestic product would rise by an additional 6.7 percent, a cumulative increase of $10 trillion (after taking inflation into account) by the year 2050, the report estimated.


Robert G. Lynch, an economist who wrote the Washington Center report, explained why he took the trouble to make these what-if calculations.


“One of the main goals was to see how we could promote more widely shared and faster economic growth,” he said. In the three decades that followed the end of World War II, almost all Americans, no matter where they fell on the earnings scale, enjoyed at least a doubling of their real incomes.


But that balanced growth has evaporated. While those at the top have continued to experience robust income increases, everyone else’s income has either stalled or dropped. The average income of the bottom 20 percent of households sank by more than 8 percent from 1973 to 2013, while the inflation-adjusted incomes of the top 20 percent grew by about 60 percent, according to the report. The top 5 percent enjoyed an 80 percent jump.


One point of this exercise, Mr. Lynch explained, is to show that the added cost of improving educational achievement at the bottom would be more than made up for by the rise in economic output and tax revenue….


The report includes the types of changes, which include expanding early childhood education, reducing exposure to lead paint and starting school later so teenagers can get more sleep, that the center views as necessary to raise achievement scores, though it does not include specific costs in its calculations.


The report also notes how widely achievement scores vary within the United States, not only from state to state but county to county. Montgomery County, a generally affluent suburban area in Maryland just outside of Washington, for example, was able to reduce the gap and increase scores after instituting all-day kindergarten programs, reducing class size, investing in teacher development and reducing housing-based segregation in its schools.


All of these are good ideas, all of them should be speedily implemented. But I don’t understand how these changes by themselves will generate more and better-paying jobs to create the economic growth that is predicted. None of these proposals addresses intergenerational poverty. Schools are very important, and we should do whatever we can to make sure that every child has equal educational opportunity. But schools alone cannot reduce the source of the achievement gap, which is poverty. Nearly a quarter of our children live in poverty, the highest proportion of any advanced nation; and 51% live in families that are low-income or poor. A strategy is needed to create good jobs, good housing, and a range of services to help families live decent lives and provide for their children. That’s what other nations do. Across Europe, for example, there is a sturdy safety net that includes both school-based improvements and socioeconomic strategies to help families and communities. Some of the comments following this article make the same point.