Does "value-added" have any value?
Does "value-added" have any value?
Sent to the Los Angeles Daily News, August 25, 2010
Ramon Cortines and Arne Duncan are convinced that using increases in standardized test scores for evaluating teachers is a good idea ("Cortines: LAUSD's success depends on continued embracing of reforms," August 25).
But these "value-added" evaluations are unstable. Teachers' ratings based on previous years are weak predictors of test scores at the end of a year with new students; a teacher who succeeds in boosting scores with one group will not necessarily succeed with others. Also, different tests result in different value-added scores for the same
Sent to the Los Angeles Daily News, August 25, 2010
Ramon Cortines and Arne Duncan are convinced that using increases in standardized test scores for evaluating teachers is a good idea ("Cortines: LAUSD's success depends on continued embracing of reforms," August 25).
But these "value-added" evaluations are unstable. Teachers' ratings based on previous years are weak predictors of test scores at the end of a year with new students; a teacher who succeeds in boosting scores with one group will not necessarily succeed with others. Also, different tests result in different value-added scores for the same
