What are student growth percentiles?
A student growth percentile (SGP) describes a student's growth compared to other students with the same initial test score. SGP is similar to a standard percentile, but instead of measuring student achievement compared to peers, SGP measures comparative growth. The student growth percentile allows us to compare the growth of students at different achievement levels.
Like all percentiles, SGP is a number between 1 and 99. Receiving an SGP score of 70 indicates that you demonstrated more growth than 70 percent of your academic peers. A student with a low raw score can show high growth, and a student with a high raw score can demonstrate low growth. Similarly, two students with very different test scores can have the same SGP.
SGP is commonly used at the school, district, and state level as the primary growth metric or a key performance indicator. Traditionally, SGP is used to calculate growth year-over-year on a given exam. However, here at Test Innovators, we take advantage of our large pool of historical data to calculate SGP test-to-test on much smaller time scales.
How are student growth percentiles calculated?
Student growth percentiles are measured by calculating the raw score change between test sections of the same subject (e.g. Reading) for a given student. This difference is compared to the distribution of score changes for past students with initial section scores similar to that of the student of interest. By observing where the student’s score change falls on the distribution, we can estimate the student growth percentile based on the expected growth for the student’s initial achievement level (scores on the initial test section).
To whom are students being compared? What is an academic peer?
When calculating the SGP, students are compared to their peers with a similar achievement level on the previous exam. Peers include all Test Innovators students who completed that particular test section in the past. Raw section scores are the only factor Test Innovators takes into account when comparing peers.
Can high-scoring students still demonstrate growth?
Yes. Students with high raw scores on previous test sections will be compared to all other students who also achieved high scores in the past. Even high-performing students have varied performance; for this reason, students with high test scores may notice that simply maintaining their high achievement is indicative of growth, given the relativity of the SGP metric.
Which students receive growth percentiles?
All students (excepting those with trial accounts) will receive student growth percentiles. However, due to the nature of SGPs, students must complete at least two of the same test section in order to receive an SGP score.
What can student growth percentiles tell us?
Student growth percentiles are a descriptive metric, like test percentiles, and describe the amount of growth a student has made since the previous test. SGPs can help answer questions like the following:
- For individual students:
- Is the student growing at an appropriate rate?
- Is the student demonstrating more growth in some test sections than in others?
- For classes or groups of students:
- Are there students with low growth who may need additional support?
How will the student growth percentile data be used?
SGPs is used alongside student performance metrics to identify student needs and to further personalize our platform to meet student needs. Students can access their SGP data from the Analysis tab of their accounts by scrolling down to the “Your Growth” graph, which can be toggled to display different metrics, including SGP.
What is Average SGP and how should I interpret it?
Average Student Growth Percentile, or Average SGP, is the cumulative mean of SGP scores achieved by a student at a given time. For example, if a student completed their fourth practice exam and received a score of 40 for their third SGP, this SGP will be averaged with the student’s previous SGP scores of 50 (test 1) and 60 (test 2) and will result in an Average SGP of 50 [(40+50+60)/3]. Prior to this fourth test, the student’s Average SGP would have been 55 [(50+60)/2]. An Average SGP of 50 reflects that the student has attained the expected average growth over time. Any Average SGP above 50 indicates above-average growth from test 1 to the current period. Conversely, any Average SGP below 50 indicates below average growth over this same time period. Individual SGP scores measure student growth from test to test compared to peers with similar test scores. Average SGP is used to observe a student’s average growth over time.