Charlotte Magazine / September 2009 / Top Schools 2009

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Top Schools 2009

How We Prepared the Ranking

Our goal in compiling this year's ranking of the best public high schools in the Charlotte area was to identify those schools that not only perform well academically, but also which schools provide an environment conducive to exceptional learning. We enlisted statistician Zhi Zhang, an associate professor in the Department of Mathematics and Statistics at UNC-Charlotte, to help analyze the data and prepare the first-ever ranking of the Charlotte area's public high schools.

It's important to bear in mind that within the list itself, the differences measured are often quite small -- any school could fairly exchange places with schools one or two positions higher or lower. Therefore, we offer these rankings not as the final word on school quality, but rather as a starting point for parents, students, and educators.

BTW

The overall ranking is based on two separate rankings of all schools on two factors: environment and performance. The environment factor includes variables such as proportion of students enrolled in AP classes, average class size, proportion of fully licensed teachers, and proportion of teachers that are board certified. The performance factor includes variables such as average combined SAT score and four-year graduation rate. Schools with missing data on any of the variables used in the ranking process were deleted from the analysis.

Two sets of variables were determined: the variables for the environment factor and the variables for performance factor. For each variable of each set, a separate ranking of all schools was performed, with the smallest value in the ranking being the top-ranked school and the largest value being the bottom-ranked school. If there was a tie in the ranking, each of the schools in the tied tier shared the lowest rank value of that tier. By performing a ranking for each variable, a rank score for each variable was established for each school. Collectively, these rank scores formed a basis for our analysis. In general, there are several options in establishing scores for ranking purposes. We, however, chose to rank scores because they tend to be more robust in the sense that, if a school has an extremely low or high reading on a variable, the extremity would not dominate the school's position in the overall ranking.

For the environment factor, the average of the rank scores on all variables in the environment set was calculated for each school. Schools were then ranked based on this average rank score. The result is the environment ranking. For the performance factor, the average of the rank scores on all variables in the performance set was calculated for each school. Schools were then ranked based on this average rank score. The result is the performance ranking.

For each school, a weighted average of the two rank scores, one from the environment ranking and one from the performance ranking, was calculated with a weight of 0.25 on the environment and 0.75 on the performance. The overall ranking was then performed based on the weighted average rank scores among all schools. Schools in a tied tier share the lowest rank value in that tier.

Our primary sources for data are listed below. In cases where information was not available for a particular school, we contacted the school at least twice to gather the data. Some schools did not return our phone calls.

The 2008-2009 percent graduation rate for all public schools can be found at: ayp.ncpublicschools.org.

The 2008-2009 SAT reports for all N.C. public schools can be found at: dpi.state.nc.us/docs/newsroom/news/2009-10/0825/
sat-report-final.pdf. (PDF)

Enrollment, percent enrollment in Advanced Placement courses, and all teacher data for 2007-2008 can be found at: ncreportcards.org/src.
To find out how the North Carolina Department of Education calculates cohort graduation rate, go to: dpi.state.nc.us/newsroom/facts/measurements/graduationrate.

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