A little something to give back to the wonderful SBG community on the web: my version of a letter explaining "the how" and more importantly, "the why" of my SBG implementation.
I've adapted sentences from similar letters shared by other teachers using SBG (apologies - I mixed up the material to the point I can't identify individual authors any more!), and then extended for my own context. I also felt I should add some FAQ style paragraphs at the end of the document to help address any concerns. When I wrote this letter I very carefully avoided using the SBG terminology or any sense this was something to make a fuss about. I think it's important to reassure people this is a normal way to work with a class - the only thing that is different is that the final topic test result is no longer the main form of grading and that students can do repeat attempts to improve their grades. Amazing how such a small change in the way of thinking about assessment can have such a massive impact on teaching and learning!