This post stems from a conversation I had with my colleague over a pint a few months ago. We were talking about ways of giving feedback on students' writing that are considered sufficient for large classes.
When teachers have a small class of learners to work with, it is relatively easy to give each individual detailed feedback. Some teachers use correction codes, whereas others may provide comments along the lines of 'good points' and 'things to work on'.
In large classes, however, this approach is time-consuming at best and impractical at worst. What I usually do is to read through each student's written work first - it usually takes me a minute or two to read a 250-word essay or article. This gives me a brief idea of a student's strengths and weaknesses. Then I spend another few minutes or so writing my overall comments. In a class of 15 students, it usually takes less than two hours.
To deal with language errors, I select sentences from various students' written work - both good examples and sentences with errors - and compile them in a single Word document. In the next lesson, my students discuss these sentences; they often recognise their own writing! This discussion task is a form of delayed error correction with peer correction in the feedback stage.