I came up with the following formula for use in Excel:<BR><BR>=IF(A2>95.9,"A+",IF(A2>92.9,"A",IF(A2>89.9,"A-", IF(A2>85.9,"B+",IF(A2>82.9,"B",IF(A2>79.9,"B-",IF(A2>75 ...

How good is one teacher compared with another? A growing number of school districts have adopted a system called value-added modeling to answer that question, provoking battles from Washington to Los ...