Feedback that a learner can act on

A page of corrections is a verdict, not instruction.

Written work returned covered in corrections communicates volume of error and very little else. The student cannot tell which errors matter, which are systematic, or what to do differently, and the most common response is to file it.

Selective correction works better and is less work. Choosing two error types, marking only those, and explaining why they matter gives the student something achievable. The others have not gone away and can be addressed in a later cycle.

Codes help if they are taught and used consistently, and are useless otherwise. A student who knows what a particular mark means can self-correct, which is the point; one who does not simply sees more red.

The most valuable feedback in this setting is frequently about what the student is doing well, specifically. Adults in an intensive programme lose confidence rapidly, and being told precisely which thing has improved does more for subsequent effort than the correction of any particular error.

It is also worth teaching students how the test is marked rather than only what it contains. Adult learners are generally capable of understanding assessment criteria and frequently improve substantially once they know what is actually being rewarded, which is information that no amount of practice testing conveys on its own.