Overview
This article provides an in-depth look at how the Sisra exclusive measure, SPI (Subject Progress Index) is calculated. This can help with troubleshooting figures, and provides insight into the calculations behind the measure.
Calculating a student's SPI score
The following video shows how the SPI is calculated:
To calculate a student’s SPI in a particular qualification, Sisra Analytics looks at all students with the same KS2 prior attainment score in the Sisra collaborative data, as well as their grade points in that specific subject area. Their grade points are then averaged to calculate an overall collaborative average point score. This average is then subtracted from the student’s points score to produce the SPI figure:
Student SPI = (Grade Points – Collaborative Average)
For example, the following student has a KS2 average prior attainment score of 96 and has achieved a grade 6 in English Language. So, to calculate this student’s SPI score, Analytics would find the average point score in English Language for all students with the same KS2 prior attainment score (3.22 in 2024) and subtract this from the student’s point score:
6 – 3.22* = 2.78 to 2 decimal places.
This indicates the student is performing just under 3 grade points better in this qualification than other students in the collaboration with the same average prior attainment score (96 in this example).
The following screenshot is taken from the Grades List report > Student level, which shows each student’s SPI figure in the blue Subject Progress Index column and a visual representation in the SPI Chart column.
You can also use the average SPI figure to compare your students' overall performance by going to the Grades area - Totals report - Students level (selecting All A8 Quals in Grade Type in the Options tab).
Calculating class or qualification SPI scores
SPI scores at class or qualification level are calculated by totalling the scores of the students within that class or qualification, and dividing this by the number of students, showing an average SPI for the class or qualification.
This allows you to compare the performance of your classes or qualifications to one another.
Class/Qualification SPI = Total of students SPI scores ÷ Number of students included
Positive SPI
When viewing the Overview or Total reports, you see a Positive SPI column. This shows the count or percentage of students based on the report level you’re viewing, who have achieved an SPI score on or above 0.
SPI warning icons
The icons below appear at the Student level to highlight specific SPI scores, helping with your analysis:
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Caution, one of the following applies: (1) Low cohort in the Data Collaboration (DC) for this qualification (1a) DC data may be grouped with other qualifications. (2) Qualification unapproved in this DC year. This can be due to a qualification having low uptake across schools opted into our Data Collaboration, therefore, the data on your students’ performance is being compared with may not be as accurate. In some cases, the qualification has been grouped with other closely aligned qualifications to make the comparisons more robust. This may be displayed for new qualifications, which have not yet been reported on within the published Data Collaboration event, or if the qualification was previously unapproved, and no official data is available. |
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Difference calculated using collaboration data with low student counts. This can be due to the number of students with a particular prior attainment being low enough that the figures may not provide a true indication of progression, but can still give an idea of how the students have performed compared to others with the same prior attainment. The number of students that would cause this icon can vary based on the Data Collaboration data being used - in 2024, this was between 10-24 students. |
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Difference cannot be calculated due to suppression of Collaboration Data / Collaboration Data suppressed due to low student count. This may occur when the number of students with a specific prior attainment is low, making it impossible to calculate a meaningful difference or SPI score (this wouldn’t provide a true indication of progression). The number of students that would cause this icon can vary based on the Data Collaboration data being used - in 2024, this was between 0-9 students. |
Related information
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