I don't know where the paper can be freely accessed. Looking at the last sentence of the abstract, I wonder if the real answer is to bring back ability grouping for all students.
http://www.nber.org/papers/w20453Does Gifted Education Work? For Which Students?
David Card, Laura Giuliano
NBER Working Paper No. 20453
Issued in September 2014
Abstract:
Education policy makers have struggled for decades with the question
of how to best serve high ability K‐12 students. As in the debate
over selective college admissions, a key issue is targeting. Should
gifted and talented programs be allocated on the basis of cognitive
ability, or a broader combination of ability and achievement? Should
there be a single admission threshold, or a lower bar for
disadvantaged students? We use data from a large urban school
district to study the impacts of assignment to separate gifted
classrooms on three distinct groups of fourth grade students:
non-disadvantaged students with IQ scores ≥130; subsidized lunch
participants and English language learners with IQ scores ≥116; and
students who miss the IQ thresholds but scored highest among their
school/grade cohort in state-wide achievement tests in the previous
year. Regression discontinuity estimates based on the IQ thresholds
for the first two groups show no effects on reading or math
achievement at the end of fourth grade. In contrast, estimates based
on test score ranks for the third group show significant gains in
reading and math, concentrated among lower-income and black and
Hispanic students. The math gains persist to fifth grade and are
also reflected in fifth grade science scores. Our findings suggest
that a separate classroom environment is more effective for students
selected on past achievement - particularly disadvantaged students
who are often excluded from gifted and talented programs.
