Once in a while, you can hear teachers talking about which kids they're accountable for and which they're not. Kids new to the US, for example, don't take or don't have their ISAT scores included in a schools AYP rating (though they take other tests to measure their knowledge and acquisition of English).
A newspaper column from Dallas reminds us that there's another, less intentional kind of unaccountable -- the kids who transfer in after a certain date (October 27 in Dallas -- I don't know what it is here). The writer calls it: "New Kids Stop Mattering Day" – the day after which any new students enrolling at your school won't be counted in next spring's test scores.
According to one study, as many as 20 percent of kids in some Texas schools are excluded from the testing because of late enrollment, and the state recently tried to exclude even more kids from testing by requiring that they be at the same school two years in a row to be counted.