Update Re: Ratings Publication, February 18, 2021
In response to the cancellation of various state and local assessments, GreatPhillySchools will not update the ratings this year. The GreatPhillySchools academic ratings will remain unchanged and continued to be based on standardized testing outcomes from 2018-2019 since no new standardized testing data are available from SY 2019-20 due to the COVID-19 pandemic. Due to similar circumstances, the attendance and school safety ratings will also remain unchanged for the 2021-2022 School Year.
GreatPhillySchools (“GPS”) school profiles include the following ratings:
- An Overall rating
- Academic achievement ratings in Math, Reading, Science
- Non-academic ratings for School Incidents, and Attendance
- High schools also receive a College Bound rating
The ratings provide a snapshot of school performance in each category by comparing each school’s outcomes to other schools serving similar grade levels. School outcomes for each rating category come from various measures. See descriptions of the specific measures used for each rating by reviewing: GreatPhillySchools Data Sources (2021)
A school’s Overall rating is calculated by weighting each of the other rating categories as follows:
For Elementary and Middle Schools (Grades K-5 and Grades 6-8):
- Academic Achievements: 70% (35% math and 35% reading)
- Student Attendance: 25%
- School Incidents: 5%
For High Schools (Grades 9-12):
- Academic Achievements: 50% (25% math and 25% reading)
- College Bound: 20%
- Student Attendance: 25%
- School Incidents: 5%
The ratings are determined by school performance in each category on a scale from 1 to 10 based on their decile ranking. GPS uses interval-based deciles to produce ratings. Unlike traditional deciles that require forced differentiation between schools with similar performance, interval-based deciles allow for cut points defined by the range of existing school performance and groups schools with similar performance.
GPS uses two variations of interval-based deciles:
- Equal Interval Deciles: The range between the highest-performing school and the lowest-performing school is divided into 10 equal tiers based on the performance metric. Any two schools with the same relative gap in performance will have a similar relative gap in performance tier. Equal interval deciles are used for the Overall rating and the Academic, Attendance and College Bound ratings.
- Logarithmic Interval Deciles: The range between the highest-performing and lowest-performing school is divided into 10 exponentially increasing size tiers based on the performance metric. Any two schools with the same relative exponential difference in performance will have a similar relative gap in performance tier. Logarithmic interval deciles are used for GPS’ School Incident ratings.
Rating Schools Based on Grade Level
With the exception of the ‘Overall’ rating, schools are grouped together in three categories based on highest grade level served (3-5, 6-8, and 9-12). For example, a school serving grades 6 through 12 would be labeled as a “High School”. The decile ratings for schools are then averaged together on a weighted basis for elementary/middle schools, and high schools (see above for rating weights). Schools are then ranked according to their weighted overall averages and deciled in equal-size increments from the top end to the bottom end of the range. All non-special admit schools are ranked and sorted independently from District Special Admit Schools.
By grouping schools based on grade levels, we compare performance of students in the same grade levels with one another. This allows us to compare the performance of schools serving only elementary and/or middle school grades (i.e., K-5 or 6-8) to the performance of schools serving a wider grade band).
Academic Achievement Sub-Ratings
Math, Reading and Science: These ratings represent the percentage of students performing in the four performance bands in the respective subject, as measured by the most recently available standardized test data. The performance bands are as follows: (1) Below Basic; (2) Basic; (3) Proficient; and (4) Advanced.
The weighting for each band is listed below and is used to calculate each school’s raw score. The raw score is then compared to other schools in Philadelphia using equal interval deciles.
See GreatPhillySchools Data Sources (2021)for information about the standardized test data sources.
Performance Band Weights
The weighting for each band is used to calculate each school’s raw score. The raw score is then compared to other schools in Philadelphia using equal interval deciles.
- 3 x Percent of Student Scoring Advanced
- 2 x Percent of Students Scoring Proficient
- 1 x Percent of Students Scoring Basic
- No points for Students Scoring at Below Basic
This approach is intended to better differentiate between schools at both the top and the bottom performance ranges. While a score of ‘Basic’ is not sufficient, this weighting recognizes schools with fewer students performing in the ‘Below Basic’ tier and rewards schools with students scoring in the ‘Advanced’ tier.
GPS then creates a list of all schools sorted highest to lowest by their raw scores for each subject area. Equal Interval Deciles are used to sort those schools into 10 groups with equal increments between them, known as deciles. The hi the top of that list is assigned a “10”, the next group assigned a “9”, and so on. All non-special admit schools are ranked and sorted independently.
GPS ratings are comparative — meaning a school that is assigned a “10” represents the highest performing amongst all Philadelphia schools for that particular metric; likewise, a school that is assigned a “1” represents the lowest performing amongst all Philadelphia schools for that metric. For example, a school assigned a “10” in reading does not mean that 100% of their students performed at or above grade level in reading in the most recent standardized test. Instead, a “10” rating means the school is ranked in the top group of all Philadelphia schools for their reading.
High Academic Growth (Not Included in Ratings)
GPS includes a green arrow indicator for public district and charter schools that have shown significant evidence of student growth on state assessments over the most recent three years. The underlying data for this indicator comes from the Pennsylvania Value Added Assessment System (PVAAS). PVAAS is not a test. PVAAS is an analysis that uses PSSA and Keystone test results to predict and measure student academic growth from one year to the next. GPS uses PVAAS 3-year Average Growth Index (AGI) data, in reading and math, for each school. Schools with a 3-year AGI of 2.0 or higher in both reading and math receive a “High Academic Growth” indicator (green arrow) on their profiles. An AGI of 2 indicates significant evidence that the school exceeded the norm for Pennsylvania Academic Growth.
Note: Catholic and private schools do not receive a PVAAS report and therefore are not eligible for the “High Academic Growth” (green arrow) inds not mean that Catholic and private schools are not demonstrating significant student growth. Rather, there is not currently a system to reliably compare private school growth to public district and charter schools.
Attendance: This rating represents the percentage of students who attended 95% or more of enrolled instructional days. The attendance outcomes for all schools are sorted from highest to lowest, and Equal Interval Deciles generate ratings on a scale of 1 to 10 for each school.
School Incidents: This rating represents the reported incident count per 100 students. We calculate this rating based on the number of reportable incidents, as reported by schools. See GreatPhillySchools Data Sources (2021) for more information.
School Incidents Calculation
Each school’s total incident count is divided by the school’s total enrollment, then multiplied by 100 in order to calculate an incident rate comparable across schools with various student enrollment. For example, a school with 1,000 students and 20 incidents has an incident rate of 2-per-100 students, while a school of 300 students and 9 incidents has an incident rate of 3-per-100. Incident Count data for all schools is then sorted from highest to lowest, divided into ten different groups, then assigned school incident ratings on a scale of 1 to 10.
Unlike other rating categories, the groups for school incident ratings are established on a logarithmic scale, rather than in equal-sized increments, meaning each successive increment is exponentially larger. This allows for greater articulation of differences at the low end of the scale. On an Equal Interval decile scale, a school with four incidents per 100 students might be rated the same as a school with oent per 100, even though that represents four times as many incidents. A 10 rating for school incidents means a school falls into the band of schools with the fewest number of incidents per 100 students.
College Bound: This rating represents the percentage of annual graduates who enroll in any postsecondary institution in the first fall following their graduation date. Schools are then divided into equal-sized groups to create ratings from 1 to 10, with 10 representing the highest college enrollment rates.
Disclaimer: Data collection and analysis for GPS was managed by the Philadelphia School Partnership in consultation with Data Partners LLC, a data analytics consulting firm with significant experience analyzing and modeling student and school performance data. Guidance and assistance was also provided by the Pennsylvania Department of Education, McGraw-Hill’s CTB division (producer of the TerraNova) and Frontier 21 Solutions, an education research company.
Note: We have taken a number of steps to ensure the accuracy of the data reported here. Nonetheless, there may still be errors in the data files that we have not yet identified. If you believe you have found an error in the data, please contact us here. If there are errors in an official data source, those errors could affect the ratings produced by GPS. Also, it is reasonable to expect that not all data collected by these institutions were tabulated in exactly the same way. GPS ratings are meant to be used as a helpful guide, and should not be considered a final judgment about a given school.
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