When cohorts are small, show the student numbers and resist treating every percentage movement as a trend.
Results percentages become increasingly unstable as cohort size falls.
This matters particularly for smaller A-Level subjects, optional GCSEs and subjects taught in small sixth forms or colleges.
Always report the number of students as well as the percentage.
In a cohort of ten students, one student represents ten percentage points. A dramatic-looking year-on-year movement may therefore involve only one or two people.
A simple calculation is useful:
one student ÷ cohort size × 100
So one student represents:
This should influence how confidently you describe changes.
Suppose A*–B falls from 67% to 58%.
That sounds substantial.
But if one cohort contained 12 students and the other contained 14, the change may represent a difference of only one or two grades.
State both:
7 of 12 students, 58%
rather than simply:
58%
A three- or five-year picture may be more informative than comparing two small cohorts.
You may discover that results naturally fluctuate as the characteristics of each small group change.
That does not mean trends should be ignored, but it does mean they should be interpreted cautiously.
A national result may be based on thousands of entries.
Your departmental result may be based on 11.
A difference of eight percentage points between the two does not automatically represent a meaningful gap.
Ask how many students would need to receive a different grade for the apparent gap to disappear.
With a small cohort, you can often complement aggregate statistics with deeper knowledge of individual performance.
Scripts, question-level data, prior assessment evidence and the circumstances of the cohort can add considerably more insight than another percentage calculation.
Instead of:
“Top grades fell significantly.”
Consider:
“Three of 11 students achieved A*–A compared with four of 12 last year. Given the small cohorts, this difference should be interpreted cautiously.”
That is accurate without being evasive.
Use the tutor2u Results Explorer to provide national context, but keep the size of your own cohort visible throughout the analysis.
Last checked August 2026. This is a plain-English summary of official guidance; always check the linked Ofqual, JCQ and exam-board pages for the definitive rules, which can change.
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