Hi The French,
Yes it is a model for teaching writing.
More information is available here: writingfix.com/traits.htm
Basically, this method appears to break down the components of writing e.g. organization, voice, word choice. By training students on each of the components, it is hoped that the students can piece the skills learnt together to write well.
I'm actually looking for broad effective strategies for teaching writing. Any help in this area will be appreciated.