Those who believe all is well in America’s public schools are pointing to the 10 percentage-point gain in high school graduation rates over the past decade, with 80 percent of high schoolers now completing high school.

To the extent there is any problem, they attribute flagging standards of American education to the rising numbers of children from immigrant and other disadvantaged backgrounds. But a just-released report from the Education Department reveals that high school seniors have shown no signs of improvement in either math and reading between 2009 and 2013.