An interesting chart is making the rounds. It shows how Charlotte-Mecklenburg Schools would have performed on the state's A-F grades if the formula were weighted differently.
Under the law, a school's grade is based 80 percent on test scores and 20 percent on how much growth that school has shown. As a result, the grades were no surprise: Schools filled with poor kids did worse than schools with few poor kids.
Some critics, including the Observer editorial board, argue that the A-F grades would be vastly improved if more weight was given to how much growth a school has shown, not only where it is at one point in time.
This chart, which comes from CMS, shows what would happen.
Under the 80/20 formula, 47 CMS schools were given a D or F. If the formula were 50-50, no schools would get an F and 16 would get a D. If the formula were 20-80 (80 percent of the grade based on growth), five schools would get a D and none would get an F.
This is not tinkering the formula to make your schools get artificially better grades. It's tinkering the formula to more properly weight how much progress a school is making, which is an important measure. It just so happens that this more accurate gauge also reveals that public schools aren't performing as badly as the state grades lead you to believe.