True, tracking has worked hard to earn its bad rap. Inflexible, racially biased tracks did and do constrain many students. When tracking is paired with appropriate differentiation and flexibility between tracks, however, it becomes an effective method for meeting the needs of mathematics students. A study by Chiu, Beru and Watley (2008) yielded positive effects of tracking on both high and low performers (http://www.eric.ed.gov/ERICWebPortal/search/recordDetails.jsp?ERICExtSearch_SearchValue_0=EJ816768&searchtype=keyword&ERICExtSearch_SearchType_0=no&_pageLabel=RecordDetails&accno=EJ816768&_nfls=false&source=ae). Loveless' 2009 study sponsored by the Fordham Institute regarding Massachusetts schools showed that there were 6% more students in advanced classes in tracked programs and a 3% higher representation of low SES students in those classes as well as higher scores for the high achievers on the MCAT (http://www.sbsdk12.org/programs/gate/documents/200912_Detracking.pdf). Studies of Chicago's double dose algebra approach where students who are low performers are given a second algebra support class that involves discussion, hands-on practice and reinforcement of concepts, significantly increased the success rates of the students in math AND English, as well as the student's likelihood of completing high school and going on to post secondary education (http://ccsr.uchicago.edu/sites/default/files/publications/Double%20Dose-7%20Final%20082610.pdf and http://educationnext.org/a-double-dose-of-algebra/)
Further, much research supports the concept that gifted children are hurt by heterogeneous tracking. For a sampling:
"Harrison Bergeron" is a satirical and dystopian science-fiction short story written by Kurt Vonnegut Jr. in which people are made equal by donning handicapping devices. No one is allowed to be better at anything than others. This is not the model we wish for our education system. We want our best students to become our movers, shakers and inventors of the future. If we insist on providing an equal education to all, we are meeting Vonnegut's ideal. If we provide high achievers access everywhere to fast moving, advanced programs, and high quality programs to all, we are meeting the goal of helping students reach their individual potentials. Can a national curriculum provide some frame work for this? Yes. But just like you want students to move flexibly between achievement groups, I want them to move flexibly between "grades" within the curriculum. Let's encourage our high performers to go above grade level and test them there. Let's support our struggling students and allow the very lowest to learn and test below grade level until they can meaningfully be tested at grade level.