Michelle Rhee's Teacher Evaluation System Deemed "Idiotic"

From Aaron Pallas, posting at Valerie Strauss's blog at WaPo:

. . . .There’s no polite way to say this: The procedures described in the DCPS IMPACT Guidebook for producing a value-added score are idiotic. These procedures warrant this harsh characterization because they make a preposterous assumption based on a misunderstanding of the properties of the DC Comprehensive Assessment System (DC CAS).  . . . .

Do read on.