Originally Posted by Val
But CTY was always about the special needs of gifted students, and I fear that too many canned courses designed for the needs of the majority will dilute their brand and damage one of the few really good options for very smart kids. /soapbox rant

Some research from EPGY says that their curriculum is effective for a substantial fraction of low-income students.

http://epgy.stanford.edu/research/Final%203%20Effectiveness%20Study%20Report%207.18.09.pdf
Patrick Suppes, Paul W. Holland, Yuanan Hu, and Minh-thien Vu (2009) Effectiveness of Stanford’s EPGY Online Math K-5 Course in Eight Title I Elementary Schools in Three California School Districts, 2006-2007

Abstract
Stanford University’s Education Program for Gifted Youth (EPGY) conducted a randomized
treatment experiment during the 2006-2007 school year to test the efficacy, for Title I students, of
the EGPY Kindergarten through Grade 5 Mathematics Course Sequence (Math K-5). While the
EPGY curriculum was originally developed for gifted students in any grade, the students in this
study were not selected as gifted but were simply the students in the Title I schools. If we restrict
attention to those EPGY students who were in the top half of the distribution of correct first
attempts on the EPGY exercises (a measure of work and engagement in the EPGY curriculum)
we see substantial and statistically significant improvements in the CST07 test scores over the
scores of matched control students. The effects in second grade appear to be larger than those in
grades 3 to 5.

Key words: Randomized treatment experiment, matching, EPGY, Correct first attempts, HLM,
Proficiency Levels, CST, predicting future test results, Bayesian Classifiers, Mahalanobis
distance, Learning curves.