The routine in one sentence
Duffspin is a short classroom routine for GCSE maths: a student takes a wrong answer, labels the exact step where the method broke, and then reworks the same question from that step under timed conditions. It is not a general revision slogan; it is a repeatable correction cycle that works best on multi-step problems such as solving equations, rearranging formulae, and calculating with fractions.
Context: why a crossed-out answer is a poor starting point
Most marking stops at the wrong final answer. A pupil sees a red cross, copies the correct method from the board, and moves on. The problem is that the original error remains unlocated: was it a sign slip, a misread question, a missing unit, or a breakdown in algebraic manipulation? Without that diagnosis, the next attempt is guesswork.
Duffspin changes the object of attention from the answer to the faulty step. A student writes the original working in one column and, beside it, a one-line label for the first incorrect move. For example, in solving 3(x + 4) = 27, the label might read “expanded 3x + 4 instead of 3x + 12”. That single label gives the teacher a concrete target and gives the student a specific repair task.
Development: the three-minute cycle
The routine is deliberately short so it can fit into a lesson starter or a tutoring session without displacing new content. It has three timed parts.
- Minute 1 — Locate. The student finds the first incorrect line in their own working and writes a short diagnosis. The diagnosis must name the operation or concept, not just say “careless mistake”.
- Minute 2 — Rework. The student covers the original solution and redoes the question from the faulty step, speaking the rule aloud if working with a tutor.
- Minute 3 — Swap. The student applies the same repair to a near-identical question with one changed number or sign. This checks whether the correction transfers.
A tutor can model the routine once, then hand students a short duffspin card with the three prompts: “Where did it break?”, “What rule applies?”, and “Can I do it with a changed number?” The card keeps the routine concrete and reduces the temptation to skip straight to the right answer.
Result: what changes in the next lesson
The measurable result is not a sudden jump in every score; it is a reduction in repeated errors of the same type. Teachers who use the cycle can group students by diagnosis — sign errors, fraction addition, formula rearrangement — and reteach a single step to the whole group. Students also gain a sharper vocabulary for self-correction, which makes peer marking more useful.
Duffspin works because it treats an error as data rather than failure. The student leaves the routine with one named fault, one reworked step, and one transfer check. That is a small enough workload to repeat daily, and specific enough to change what happens on the next question.
