Using the textbase-situation model of discourse processing and assuming a distinction of learning (recall of text contents) and understanding (relating different parts of text contents or text to non-text contents), it was found that individuals reading text contents from a number of sources who wrote an argumentative essay about the contents and then rated content elements for importance developed a better understanding of the contents than individuals writing a narrative essay and making importance ratings either before or after writing.

http://www.sciencedirect.com/science/journal/08830355