Via Education Week:
In addition to the evaluations of performance within those individual categories, readers will find overall, summative letter grades and scores for the nation and the states. Those grades incorporate the most recent information available across each of the six categories that make up the full Quality Counts report card. Each category carries equal weight when calculating the summative scores.
For the fifth year in a row, Maryland posts the nation's highest overall grade. Scoring 87.5 and earning a B-plus, Maryland finishes 3.4 points ahead of second-place Massachusetts, which is followed by New York and Virginia. For the first time, Kentucky (10th) joins the top-10 states, while Florida (sixth) regains its top-10 ranking after falling to 11th place in 2012. At the other end of the rankings, South Dakota was awarded a grade of D-plus. A majority of states fell near the middle of the grading curve, with 38 states earning grades between a C-minus and a C-plus. The United States as a whole gained a half-point from last year, bringing the national grade up to a C-plus, from a C.