A teacher's guide to interpreting repeated mistakes
Five mistake types, how to tell them apart from a student's working, and the different fix each one needs — with a tally tool.
- Who it's for
- Teachers and tutors reviewing test papers.
- What it helps with
- Match the response to the cause of a mistake, rather than reteaching everything.
- Written by
- Heramb.study editorial team
- Last reviewed
When the same student gets the same kind of question wrong twice, the instinct is to reteach the topic. That works for one kind of mistake. For the other four, it wastes time — and can make a student who already understands the idea feel they don't.
Five types of mistake
| Type | How it shows up | What helps |
|---|---|---|
| Concept gap | Wrong approach from the start; can't explain why a method applies. | Reteach the idea with a fresh example, then check understanding with 2–3 'explain why' questions before more practice. |
| Method / procedure error | Right idea, but steps go wrong — sign errors in a derivation, wrong unit conversion, skipped step. | Model the full worked method once, then give short sets of the same step until it is fluent. |
| Careless slip | Student spots the error immediately when shown; arithmetic or copying mistakes. | Teach a quick checking routine (units, signs, rough estimate) and practise it — reteaching the topic won't help. |
| Misread question | Answered a different question: missed 'NOT', wrong quantity asked, ignored a condition. | Practise underlining what is asked and any conditions before solving; use questions with deliberate traps. |
| Time pressure | Correct when untimed; errors cluster at the end of the paper or in long questions. | Use timed mini-sets and teach when to skip and return; check the order the student attempts sections. |
How to tell them apart
- Read the working, not only the answer. Where does it first go wrong?
- Ask the student to explain one wrong answer. If they spot the error immediately, it's probably careless or misreading; if they defend the wrong approach, it's likely a concept gap.
- Try it untimed. If they get it right without the clock, time pressure is the issue.
- Look across questions. One slip is noise. The same type of error three times is a pattern.
Mistake-pattern tally
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Go through one student's wrong answers (or a sample from the class) and count each by type.
Concept gap
Wrong approach from the start; can't explain why a method applies.
Method / procedure error
Right idea, but steps go wrong — sign errors in a derivation, wrong unit conversion, skipped step.
Careless slip
Student spots the error immediately when shown; arithmetic or copying mistakes.
Misread question
Answered a different question: missed 'NOT', wrong quantity asked, ignored a condition.
Time pressure
Correct when untimed; errors cluster at the end of the paper or in long questions.
Your pattern will appear here once you start counting.
Building a "repeat mistakes" habit
Ask students to keep a single page listing mistakes they've made more than once, with the corrected version and the type. Reviewing it before each test is quick and directly targets the habits most likely to cost marks. The readiness diagnostic includes this habit.
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
- Dunlosky, J. et al. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4–58. doi.org/10.1177/1529100612453266
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