How to compare two assessments fairly
Why a rise from 60% to 66% may mean nothing, how to compare topic by topic, and a calculator that separates real change from noise.
- Who it's for
- Teachers, tutors and institute leads who report improvement.
- What it helps with
- Avoid over-claiming or missing real progress when comparing tests.
- Written by
- Heramb.study editorial team
- Last reviewed
"Average went up from 60% to 66%" sounds like progress. It might be. It might also be an easier paper, a different mix of topics, or normal variation. Before reporting improvement — to a student, a parent or your management — check three things.
1. Are the tests comparable?
Compare like with like: the same topics, similar question types, similar length and time limit. A follow-up check that only includes the topics you practised is fine, as long as you compare it against the same topics in the first test — not against the whole first paper.
2. Compare topic by topic, not totals
A stable total can hide a big gain in one topic and a loss in another. Topic-level comparison shows both, and tells you where your teaching made a difference.
3. Allow a margin for noise
Two different tests are never exactly equal, and students have good and bad days. Treat small changes — a few percentage points — as no clear change. The calculator lets you choose the margin. Use a wider margin when topics have only a handful of questions.
Assessment comparison calculator
Runs in your browser — marks you type, paste or upload aren't sent to us
Enter each topic's percentage on two assessments. Changes within the margin are reported as "no clear change".
5 is a sensible default when the two tests are similar; use 8–10 if they differ in length or difficulty.
What to do with the result
- Improved: move the topic to maintenance — occasional mixed practice.
- No clear change: check whether the practice targeted the actual cause of mistakes.
- Declined: first check the questions were comparable; then look at the mistake types.
Record results in a progress report so the student can see the change too.
Sources
- Black, P. & Wiliam, D. (1998). Assessment and classroom learning. Assessment in Education: Principles, Policy & Practice, 5(1), 7–74. doi.org/10.1080/0969595980050102
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