Geoff Petty - Remarkable results as students assess each others’ work

Geoff Petty discusses how teachers deliberately taking a back seat and letting students assess their peers' work, using ‘model answers' or 'worked solutions', can be so rewarding for their learning and lead to a marked improvement in their performance.

Geoff Petty is author of Teaching Today and Evidence Based Teaching and has trained staff in more than 300 colleges and schools. This article first appeared in InTuition - the quarterly journal for members of The Society for Education and Training (SET).

Most teachers work too hard. Are you one of them? It’s good to know that many of the teaching methods that do best in rigorous classroom trials require the teacher to do less, and the students to do more.

Here, for example, is a strategy which Graham Gibbs found almost doubled attainment (quoted in John Biggs, 2003). At least as interesting as the strategy itself is why it worked. Have a look at the method described in the bullets below. Students are warned about the process before they start.


Why is the method so effective?

  • Students answer questions and put their name on their work
  • They hand these in, and you give them out to other students to mark. (It’s best if students do not know who will mark their work.)
  • Students mark their peers’ work, using ‘model answers’ or ‘worked solutions’ and a marking scheme provided by you. (If you worry that students might not mark responsibly, you could ask markers to initial their marking.)
  • You collect all the marked work and hand students back their peer-assessed answers. Students each keep the model answers and marking scheme. (Most students will probably check the quality of the peer’s marking, but you needn’t.)
  • You ask the students what issues came up? What judgements were hard to make?

Gibbs reports that the teacher did not take down the marks that the students obtained, though you could if you wish. Remarkably, the average mark on the unit rose from around 45% to around 75% as a result of this strategy.


The advantages of repetition

First, there is a good deal of repetition. The student does the questions, looks carefully at the model answers while marking their peer’s work, and will then probably check the peer’s marking of their own work by looking again at the model answers. It’s actually helpful that students don’t trust each other’s marking, as this encourages them to look even more carefully at the model answers and how they differ from their own answers.

In this whole process, students become very clear about:

What they should have done: This comes from having to look carefully at the model answers while marking their peer’s work, and when checking the marking of their own work. What they got right: The peer marking will tell them what they got right, and they can check this marking against the model.

What they didn’t get right and how to fix it: The peer who marked their work will show them what they got wrong and, again, they can check this against the model. Helpfully, they have studied the correct answers carefully while using the model to mark the peer’s work as well as when they are checking the marking of their own work. As a result, they can easily see the gap between what they did, and what they should have done, and how to close this gap.

Another powerful aspect of peer assessment is that while students don’t seem to mind handing in poor work to you (you’re only a teacher, after all), they feel uneasy about handing over rubbish to a peer. So warning students that their work will be peer assessed will raise the standard of what they do.

The great strength of this teaching method is that it provides the students with all the information they require in order to improve. When students have completed a peer assessment, it’s useful to ask them whether they could produce better answers if they were given similar questions again. They nearly always answer ‘yes’ with great confidence. Peer assessment helps to prepare students for self-assessment, which is a vital prerequisite for self-improvement.


Self-assessment skills

When a student hands in a poor piece of work, it’s often due to poor self-assessment. This is because students need to check their work while they complete it, realise the weaknesses, and address them.

It’s their self-assessment skill that enables students to produce higher quality work. So, getting students involved in the assessment process is not laziness on the part of the teacher (honestly!). It’s the teacher developing an absolutely vital capacity for self-improvement in their students.

And while it has become traditional to ask students to mark their peers working alone, group discussion will help develop their assessment skills while creating more peer pressure to do good work.

Here is how it works:

  • Students form groups of, say, three
  • Students pass their work to the student on their right, so each student now has another student’s piece of work
  • The students in the group now take turns to mark or edit the piece of work in front of them, thinking out loud, while being watched by the other two students (one of whom did the work of course)
  • There is then discussion about any differences of opinion which you may have to adjudicate



  • John Biggs and Catherine Tang, Teaching for Quality Learning at University, 3rd Edition (2007), Open University Press.