also it is not 15-20% of the kids in the whole schools that were id'd as gifted but "in the classes that got the intervention"
One could surmise that the classes are tracked somewhat though not officially and the intervention went to the track one and track two classrooms. Also the kids with disabilities that arent inclusion wouldnt be present nor would the first two years of english language learners. they would be in separate classrooms.
I am not surprised that taking the top kids in a poor school and teaching them well and enriching them for three years resulted in 15 % of them being in the top 10% on ITBS and COGAT scores. Aslo it doesnt say whether they qualified in language arts or math or both. In alot of elementary programs only one area is necessary for identification.
however the more telling parameter will be how they do in the next three years and what happens in middle school. but that arm of the study probably isnt funded. i wish there was access to the actual study and not just news reports about what other people thought about the study. anybody have a link or a citation?