Anonymous wrote:I don't understand why some posters are saying to disregard things like test scores. Are low scores not indicative of the student performance and the level at which a teacher can teach?
Not really. I think this is what PP was getting at with the "look behind the scores" comment. For example, imagine two schools: one with a really large population of ESOL students and a small population of non-ESOL students that has a low GS rating because of lower average test scores (we'll call this "LR") and one with a large population of non-ESOL students and a small population of ESOL students and a high GS rating because of higher average scores (we'll call this "HR").
Assuming that ESOL students generally face learning and testing disadvantages, the average scores (and thus the GS ratings) are not necessarily telling you much about the teaching in the two schools (to the extent that test scores say anything about teaching, but let's assume they do). For example, if you look at the breakdowns of scores among groups, you might see that at both schools generally ESOL kids score lower than the non-ESOL kids. You might also see that while the non-ESOL kids at LR have essentially the same average scores as the non-ESOL kids HR, the ESOL kids at LR actually score higher than the ESOL kids at HR.
So why is HR the highly rated school? Because HR has fewer ESOL students, the lower scores don't impact the average very much so they end up with higher average scores and thus a higher GS rating. Conversely, at LR even though the ESOL students score better than their counterparts at HR, because there are so many of them relative to the non-ESOL population, those scores bring the average down by a much greater degree. You could look at that situation and conclude that overall, there is better teaching going on at LR because the ESOL kids score better than at HR and the non-ESOL kids score just as well. In the hypothetical, HR has such a small population of ESOL kids that the school can essentially afford to let them fail without losing their high rating while at LR teachers have to make significant gains across the ESOL population in order to move the average even just a little.
In other words, its a problem of what averages tell you -- a higher GS rating probably tells you more about the make-up of the student population than it does about the quality of the teaching. (Indeed, where the non-ESOL and ESOL students have the same average scores at LR and HR, LR's GS score would still be lower than HR based on the population numbers). That may indeed be relevant to you in making your school choice - this board is full of people who want to avoid all ESOL/SN/FARMS kids as much as possible - but it is information available in ways other than GS rating and test scores. I think this is why many people say that average test scores/GS ratings don't really give you much useful information. They are essentially proxies for demographics. Of course, people feel a lot better about themselves when they say their decisions are based on GS ratings not demographics.
They only way average test scores/GS ratings might tell you something is if you are comparing ratings at two schools that have essentially the same demographic breakdown but have significantly different ratings (i.e. not 7 v 8 but 8 v 3 or something). And of course I am not saying that the hypothetical above is always true -- it could be that at any given lower rated school, all students have lower scores than those at the higher rated schools, it's just not something you can tell from the GS score.