The Franklin Special School District Board voted this month to zone Poplar Grove School, which had previously been open-zoned. The first guiding principle behind the zoning decision was "a reasonable balance related to socio-economic demographics," according to the district's web site.
Poplar Grove is and has been the least diverse school in the district since at least 2004. Diversity goals were set back that were intended to keep Poplar Grove open-zoned. One of the early goals was 50 minority student admissions in the kindergarten class over two years.

Poplar Grove, however, has not met diversity goals in the years since then.
Moving away from race due to a Supreme Court decision, according to the Tennessean (the case was Meredith v. Jefferson County, I think), the Board started focusing on low-income student distribution. On that measure, Julie Hubbard reports that Poplar Grove is still the least diverse school in the district, with Poplar Grove's Elementary School being 14% low-income, while Franklin Elementary totals 65%.
The Board saw that gap and called it an "imbalance":
As of September 2011, there were over 50 percentage points between the school with highest number of students on free and reduced lunch and the school with the lowest number. In an effort to correct the impact that an imbalance of socio-economic students brings to schools, the Board turned its focus to developing rezoning scenarios...The plan ("Scenario 10") will be adopted in stages, to ease the transition. For the 2012-2013 school year, only 7% of the students in the district will be rezoned.
A summary of the plan is available in both English and Spanish.