LAUSD stubbornly insists on evaluating teachers on gains students make on standardized tests, called "value-added" scores ("LAUSD unveils plan to evaluate teachers, principals," April 12). This is a bad idea.
Different tests produce different value-added scores, and teachers' value-added ratings can vary from year to year, sometimes quite a bit.
Also, using value-added scores for evaluation encourages gaming the system, trying produce increases in test scores by teaching test-taking strategies, not by encouraging real learning. This is like putting a match under the thermometer and claiming you have raised the temperature of the room.