I have just about finished Part I of the Regression Labs initiative. This includes a discussion of market modeling (which includes AVMs). It will also include a down-loadable regression application that runs in Excel (this application will run until the end of the year). It is designed to download data from your local MLS (Your MLS must download to a spreadsheet). I am looking for appraisers that have been using regression analysis and can give me some input. Be watching for this article on the Lab's site.