Comment: Test score growth: don't trust it (Score 3, Interesting) 343
I realize TFA is more like the author's off-the-cuff musings and less like a rigorous study, but it does recommend looking at test score growth, and in the process fails to mention something that's both nearly obvious but almost always overlooked when discussing test score growth. When test scores grow, one is by definition comparing the scores that one group of students took on one test to the scores that another group of students got on a different test. With that in mind, there are 5 principal ways that test scores can "go up":
1. students cheat on the second test
2. the second test is easier
3. students who score low on the first test don't take the second test
4. students, who score high on the second test, were added to the testing group but did not take the first test
5. more individual students score better on the second test than perform worse on the second test
Cheating does happen, but it's probably rare. Tests can be psychologically validated to ensure constant difficulty, but this isn't done as often as it should. Nevertheless, #3 is by far the most common and least talked about way for test scores (particularly relative test scores) to improve. TFA recommends looking at the relative standing of a schools 2nd graders and 5th or 6th graders. We'd like to think that the students are being educated so successfully that their performance improves, but anyone making such a claim ought to be required to (rigorously and mathematically) prove that changes in the student population are not the primary cause. There is pretty good evidence, for example, that the high-profile improvement in the charter school that Michelle Rhee worked at was rather effective at "counseling out" the consistently low scoring students to have apparent test score gains that had little to do with their instructional program. I can well imagine the administrative staff of a school "working with" the parents to help find a school that's "a better match" to their kid's "unique learning style."