Why no compilations in "Best Album" lists?

In my Year-End Music Spectacular at my blog, I include a separate category of “Not Exactly New” albums. That includes live albums, expanded reissues, compilations, and other things that aren’t collections of new studio work.

Some choices for this year include Pavement’s Wowee Zowee: Sordid Sentinels Edition, My Morning Jacket’s Okonokos (live), and PJ Harvey’s Peel Sessions collection.