Excellence Index


The Excellence Index (EI) aims to promote the pursuit of academic excellence by rating schools on the basis of the highest levels of academic achievement. It is based on the proportion of students scoring at the highest levels on AP Exams, IB Exams, SATs, and End of Course exams, in comparison to state, national, or global norms (detailed methodology below). The index is scored out of 100, though bonus points make it possible to score above a 100. A 75 score signifies that a school has a normal level of high achievement.

The 2018 Excellence Index for high schools in Douglas County:

School 2018 EI Change from 2017
Douglas County 52 +12
Alexander 40 +15
Chapel Hill 31 +19
New Manchester 14 +4
Lithia Springs 12 +3

Combined, the EI score for the entire district is a 35. This means that on average high school students in Douglas County are more than two times LESS LIKELY to score at the highest level on exams than their peers statewide (EOC) or globally (AP, IB, SAT). Here’s the breakdown by exam:

chart (11)

We are happy to see the index go up at all schools from the previous year. This is a result, mainly, of more students scoring ‘Distinguished Learner” on EOCs (average of 7.2% across all eight subjects).


The following table shows the separate components of the Index (each component is weighed equally). The guiding concept behind the scores is that schools that have a normal proportion of students scoring at the highest levels deserve what would be an average (C) mark (75% of the points). Thus, an EI of 75 represents that the school has a typical percentage of high achievers. Thus, a component score of a 25 means students were three times less likely to score high on the exam; a score of 38 means they were about two times less likely.


The SAT Excellence Score compares the % of graduates scoring in the 90 percentile on the combined math and verbal section of the SAT. For a typical school, this would be 10%., which would translate into a score of 75. Scores are proportional to the %, so 1% translates to a score of 7.5 In 2017, the 90 percentile score was 1320.

The AP and IB Excellence Scores compare the % of all test takers scoring at the highest levels (5 for AP; 6 or 7 for IB) with global norms. In 2017, 13% of all AP exams were a 5, and 25% of all IB exams were a 6 or 7. Schools with %s at these levels would get a score of 75.

The EOC Excellence Scores are based on the % of students scoring at the level of Distinguished Learner (DL), averaged across all 8 subjects.  The average for the state was 8.9% in 2017, representing an EI score of 75.

To summarize, a 75 EI score would mean, on average, that:

  • 10% of graduates score in the 90 percentile on the combined Math and Verbal on the SAT
  • 13% of test takers score a 5 on AP Exams
  • 29% of test takers score a 6 or 7 on IB Exams
  • 8.9% scored Distinguished Learner on EOCs

To earn a 100 would mean that:

  • 13.3% of graduates score in the 90 percentile on the combined Math and Verbal on the SAT
  • 17% of test takers score a 5 on AP Exams
  • 39% of test takers score a 6 or 7 on IB Exams
  • 12% score Distinguished Learner on EOCs.

Since it is possible to score higher than these, an EI score over 100 is possible.

We previously posted the underlying data for each high school with a brief analysis:


Chapel Hill

Douglas County

Lithia Springs

New Manchester

Why the need for a new index and ranking system?

The state of Georgia uses the College and Career Readiness Performance Index (CCRPI) to rate school quality. While this method is superior to ours in some respects because it is much more comprehensive, it does not give enough credit to the highest levels of achievement, and thus barely incentivizes academic excellence. For example, it does not distinguish between Proficient and Distinguished Learners, nor between 3s, 4s, and 5s on AP exams, in calculating “Post High School Readiness.” All of these levels count the same in the index. Furthermore, the CCRPI contains a number of “participation” metrics which can earn schools higher scores if they lower the standards required to pass courses and graduate.

As for rankings systems, the US News & World Report’s best schools do not reward distinctly the highest levels of achievement. For example, their “College Readiness Index” includes % of exams taken and then only credits one passed AP exam per graduate.

What about other considerations of academic performance?

We do believe that there are other valid criteria for judging the academic performance of a school that could be included. Our Index could and should be more sophisticated and fair, and we invite criticism to help us improve it. We have already identified ways to improve the Index in the future, as time and resources allow:

  • Adjust the metric based on the scores expected for the proportion of Gifted students in a school.
  • Adjust the metric based on other factors of prior student achievement. For example, standardized test scores of middle school students. The idea in both of these is to not reward schools simply for concentrating the best students. This is an issue in our current rankings since Douglas County excels due to its high number of Gifted students in its IB program.
  • Weigh the components unequally either based on the number of exams taken or the difficulty of the exam.
  • Include a metric for students that are on a career track for post-graduation, i.e. vocational tech.
  • Include other metrics of post graduation success like % of grads getting a college degree in 5 years.

Some will criticize our index for not considering economic demographics, like poverty. While we agree that schools that face and overcome demographic challenges may be more impressive than those that have more favorable demographics, we reject the notion that standards of excellence should be different for a poorer school than a wealthier one.

Are high test scores the only way to judge the excellence of a school?

Not at all! This is an academic excellence rating only. There are many different aspects to a school’s overall excellence including school climate/ culture, artistic achievement, integrity of the school faculty, community service, etc. No single indicator should be used to judge the quality of the school; one should look at multiple evidences to make a good judgment.

Thank you for taking an interest in our Excellence Index. Please send any comments to citizens4excellence@gmail.com