The United States has the world’s most highly educated workforce, but its students face high levels of poverty, inequality and violence, according to a new report, “The Iceberg Effect,” by the National Superintendents Roundtable and the Horace Mann League.

The researchers compared the United States with the G-7 nations — Germany, France, Italy, Japan, the United Kingdom and Canada — plus Finland and China. Challenging the conventional wisdom that the U.S. school system has fallen badly behind those in other industrialized nations, they found the United States had the best long-term educational outcomes of the nine countries.

Results showed that the typical American over the age of 25 has completed 13.4 years of schooling versus 12 years in the United Kingdom, Canada and Germany and 11 years in Finland and Japan. The United States also leads in the proportion of adults with a high school diploma (89 percent) and the proportion with a bachelor’s degree (31 percent).

The U.S. was in the middle of the pack, however, in student test scores. The researchers tied lackluster student performance to social and economic indicators in which the United States trails the other countries. Only China has a higher rate of income inequality and infant mortality and more children living in poverty.

The United States also has the highest rates of death from violence and substance abuse, and it leads the other nations in the rate of teenage pregnancy. In terms of supports for families, the United States is last in spending as a percentage of national wealth and only China provides less access to preschool.