The red mark on a report can demand attention out of proportion to its actual importance.

Attention follows contrast rather than importance. One correction in red on a page of acceptable work will hold your eye for the rest of the day, while everything that was fine registers as nothing at all. The mark is doing what marks do, which is stand out; it is not making a claim about proportion. What feels like a serious judgement is usually one comment given emphasis by colour.

When something is flagged, read the whole page before you decide what it means. Counting how much was not marked is a quick and surprisingly effective way of getting the one criticism back to its real size.