Over the past two decades, gains of 1.6 percent of a standard deviation have been garnered annually by 4th- and 8th-grade students on the math, science, and reading tests administered by the National Assessment of Educational Progress (NAEP), known as the nation’s report card. An upward trajectory of 1.6 standard deviations cumulates over 20 years to 32 percent of a standard deviation, well over a year’s worth of learning.
We know a good teacher can increase the lifetime income of a classroom by over $250,000,” the president told the country in his State of the Union speech. His comment was based on a pioneering study by Chetty, Friedman, and Rockoff, published in this issue (see “Great Teaching,” Research), which for the first time combines tax data that reveal earnings at age 28 with information on student learning when that
person was in elementary school.