Chicago's Charter Schools Fail the Math Test

From Naked Capitalism, October 8.

I found this bit very telling:

In the 1970, teacher starting pay in New York City was only $2000 below that of starting salaries at top law firms. But now, as the relative status and pay of public school teachers having declined, so too has educational achievement among teachers. A recent McKinsey study found that nearly half of the K-12 teachers in the US had graduated in the bottom third of their college classes. It recommended increasing starting teacher pay from an average of $39,000 to $65,000 in high needs classes in order to attract instructors who had graduated in the top third of their classes.

So why should we be surprised that charter schools, which pay teachers less than public school teachers in the same geographic area, are having trouble delivering the educational goods?