You're not doin' fine, Oklahoma

In a new study of student-achievement growth around the world, Eric Hanushek, Ludger Woessmann, and Paul E. Peterson found the United States 25th among 40 countries in the rate of annual growth in student test score performance since the 1990s. Peterson writes:

We also found that, among states within the United States, there was also wide variation in the annual rate of growth between 1992 and 2011. When data from all the 4th and 8th grade math, reading, and science tests administered by the National Assessment of Educational Progress (NAEP) are combined, we found that the annual growth in some states (Maryland, Florida, Delaware and Massachusetts) was more than three times as great as in other states, including Iowa, Maine, Oklahoma and Wisconsin.