Understanding Subject Progress with SPI
A rise in students achieving grade 4 or above is welcome, but needs context; this year’s cohort may have entered with stronger prior attainment, while a department with weaker headline results may have performed particularly well with its students. Comparing subjects sensibly can otherwise mean hours of spreadsheets or misusing a whole-school measure.
The Subject Progress Index (SPI) in Sisra Analytics compares performance in a qualification, with students who had the same Key Stage 2 starting point in the selected Sisra Data Collaboration, at subject, group, class or student level. For heads of department reviewing exams, it contextualises grades and identifies where to investigate; for senior leaders, it provides a consistent basis for discussion without assuming identical intakes or result patterns.
How SPI Works
SPI compares students studying the same subject and sharing a KS2 prior-attainment scaled score. For each student, Sisra calculates:
Student SPI = grade points achieved − collaborative average for students with the same KS2 prior attainment
The worked example in the Sisra guide uses a student with a KS2 score of 96 who achieves grade 6 in English language against an illustrative collaborative average of 3.22 in the same subject:
6 − 3.22 = +2.78
6 − 3.22 = +2.78
The student is 2.78 grade points above the comparison average; class and qualification SPI are the mean of included student scores. Positive, zero and negative SPI indicate results respectively above, in line with or below the relevant collaborative averages. For a GCSE graded 9–1, +0.45 is just under half a grade—not a percentage increase in learning or curriculum mastery. Students may learn substantially yet have negative SPI because it compares outcomes with peers sharing their starting point, not everything occurring from Years 7–11.
SPI is available at qualification, faculty, class, student and filter-group levels; the subject average identifies where to start, while detailed reports show what lies behind it.
Why SPI & Progress 8 Can Give Different Results
Progress 8 combines attainment across qualifications counting towards Attainment 8, with defined baskets, entry rules and weightings; SPI compares the particular qualification being viewed. In English, SPI reports language and literature separately, whereas English Progress 8 uses the higher graded subject, so the two SPI figures can reveal what the combined measure cannot.
|
|
SPI |
Official Progress 8 |
|
What it compares |
Progress in a particular qualification |
Attainment across the Attainment 8 baskets |
|
Comparison data |
The selected Sisra Data Collaboration |
The relevant national cohort |
|
Students included |
Those with a KS2 prior above zero and a grade uploaded for the qualification |
Those with a valid KS2 baseline, including students without grades filling every basket |
|
Status |
A Sisra analysis measure |
A Department for Education accountability measure |
Juniper records that 1,594 schools joined the 2024 Data Collaboration: a sizeable but participating-school comparison group, not an official national figure. Differences between SPI and Progress 8 do not imply either is wrong.
Using SPI in an Exam Review
An exam review should explain more than target achievement: how students performed, where curriculum and teaching seem effective, and what needs attention. SPI helps; strong attainment may be only in line with the benchmark, while a lower grade-4 pass rate may accompany positive SPI; both require interpretation against the students taking the qualification.
At South Bromsgrove High School, Juniper’s case study shows deputy headteacher Ian using SPI as a discussion point in exam reviews and subject-leader meetings. After three annual assessment rounds, the school works with departments to identify groups needing support, using SPI alongside other student and result information.
Next test how widely a pattern is shared. A subject SPI of −0.25 might be a small cohort-wide shortfall or be driven by a few very low results - situations requiring different responses. The SPI scattergraph plots results against prior attainment, identifies students below the average, and shows collaborative averages and included subjects.
If concern centres on lower-prior-attaining history students, examine extended responses, reading, attendance and difficult-to-remember material. SPI narrows the enquiry; scripts, work and teacher knowledge explain it. Apply the same discipline to success; identify who benefited and what staff believe contributed, rather than filing away a green figure.
Who Uses It & What They Need From It
Heads of Department & Classroom Teachers
Subject leaders need to move from departmental results to classes and students. Grades reports and filters help test whether an issue is widespread or group-specific - for example, comparing disadvantaged students with others, then checking whether any gap clusters by class or starting point. Teachers can test whether patterns fit students’ work.
SPI cannot tell science teachers which misconceptions to address or English teachers which writing element to reteach; that needs subject assessment. As Stephen Tierney argues in his writing on assessment and curriculum, evaluating outcomes needs different information from responses during teaching. Use the wider comparison to identify an enquiry, then use existing departmental assessment evidence.
Senior Leaders & Data Managers
Senior leaders need a discussable overview; data managers enable it by checking inputs, qualification mapping and publishing settings. For reviews over time, the Qualification Trends report shows up to five years of SPI with grade distributions and average points per entry. Investigate apparent improvement if entries, qualifications or intake changed substantially.
Show the collaboration year; scores using different reference cohorts do not share an unchanging standard. Consider small year-to-year movement alongside other evidence, especially in small subjects.
Trust Leaders & Subject Networks
Trust leaders can use Sisra Multi-School subject reports across schools and characteristics including disadvantage, gender and SEND, directing support or departmental conversations. Sustained strong maths outcomes for lower prior attainers, for example, warrant comparing curriculum, teaching and provision across the trust.
Prepare comparisons carefully. Juniper advises consistent estimates when trusts publish reports; leaders must also consider entries, staffing and curriculum time before transferring one department’s approach.
Taking Care with Classes & Small Groups
Class comparisons look manageable but can be misleading. A top set may contain students who were already progressing faster and differences may not be explained by the original KS2 baseline.
Daisy Christodoulou explains this in relation to Progress 8 and value added; the same caution applies to class SPI. Differences may reflect allocation rather than teacher contribution. Class SPI can inform review only if staff can explain composition, teacher changes, attendance and other circumstances; it cannot establish teacher effectiveness or determine appraisal.
Small numbers add volatility; for example, in a GCSE class of ten, one student achieving two grades above the comparison average adds +0.20 to class SPI. Benchmark groups may also be small at some starting points. Sisra’s calculation guide displays warnings for small comparison groups, shows grouped qualifications and suppressed data.
What the DfE Says About Progress Data
SPI is Sisra’s measure; Progress 8 is the DfE’s official accountability measure. The DfE secondary accountability guidance says schools should not predict student or school Progress 8 before official provisional data or share individual student scores with students or parents. Progress 8 is cohort-relative and not directly comparable year to year.
Although those statements concern Progress 8, they reinforce accurate descriptions of internal analysis. Applying a historic SPI benchmark to predicted grades or mocks indicates what those inputs imply; it does not create final exam results or an official progress score and depends on reliable assessments and entered grades.
The Cohorts Without KS2 Results
Official Progress 8 was unavailable for the 2024/25 and 2025/26 cohorts because pandemic cancellations removed KS2 results. The DfE confirmed no replacement measure for 2025/26; current guidance says calculation should resume for 2026/27, when a KS2 baseline exists.
Schools assigning converted KS2 scaled scores can use Sisra for SPI and collaboration-based progress, but readers must know the conversion source and method. Juniper’s 2026 publishing guidance recommends the 2026 collaboration for SPI and Progress 8 only for 2025/26 leavers; for cohorts from 2026/27, use the 2024 collaboration and relevant 2024 official estimates based on actual KS2 scaled scores. Automatically choosing the newest dataset misses this distinction.
The DfE has also consulted on Progress 8 and Attainment 8 changes; check the published position when reporting rather than treating proposals as enacted.
Keeping Professional Judgement in the Review
Prior-attainment adjustment has value; 2023 Institute for Fiscal Studies research found prior-score adjustment crucial and supported Progress 8 as a school-effectiveness measure. This does not independently validate SPI but shows why raw attainment leaves questions unanswered.
Other evidence remains essential. In Social Mobility Commission research, leaders valued progress data but disliked decontextualised interpretation; a University of Bristol review called for clearer uncertainty and broader measures. KS2 matching does not capture attendance, disadvantage, mobility, SEND or differences created by optional versus compulsory subject entry.
Before reviewing SPI, agree the question and verify settings with the data manager; inspect included students and the result distribution; and bring relevant assessment evidence instead of demanding commentary on every figure. Discussions should produce a specific action: test whether a pattern recurs, review teaching of a difficult topic, or share another department’s approach. Attendance or support concerns may require pastoral and senior leadership involvement as well as subject expertise. Do not add data collection merely because the report permits it; give staff time to use existing information well.
Making SPI Useful in Your School
SPI gives subject leaders a prior-attainment comparison unavailable from headline and subject pass rates alone, alongside grades, student groups, trends and individual results for departmental review. It lets senior leaders discuss results, allows teachers to identify students for intervention, and enables trust subject leads to identify departments whose experience may help others.
For schools investing in analysis, the aim is less time assembling comparisons and more deciding how to respond. Training matters: staff who understand SPI can use it confidently and recognise results needing explanation.
