John Hood pointed out two weeks ago, North Carolina is one among many states that are enjoying increases in their high school graduation rates.  The piece is wicked good.

Harvard University duo Richard Murnane and Stephen Hoffman add an important analysis to the debate.

In a study published in the June 2013 issue of the Journal of Economic Literature and reprinted in Education Next, Murnane and Hoffman show that, after three decades of stagnation, graduation rates are on the rise.  According to the authors, “U.S. high school graduation rate increased by 6 percentage points, a substantial shift in a relatively short period of time.”  The source of the change was improvements in the “reading and mathematics achievement among students entering high school at the bottom of the skill distribution.”  In other words, low achievers are rising to the challenge.

The authors consider a number of educational, societal, and demographic changes that may have led to stagnation and eventual increase.  Did economic conditions produce the decades-long stagnation?  Did standards-based reform, preschool, or tougher GED exams have something to do with the recent increase ?  Perhaps we should credit other factors for the rise in graduation rates, such as a decrease in birth rates among teenagers or improvements to the criminal justice system that reduced juvenile delinquency.  It is difficult to know for sure.  But what we do know is that North Carolina’s increasing graduation rate follows a national trend, and therefore, is likely the result of broad-based, rather than state-based, reforms.