It's harder than it looks, as we take you through the year's top documentary Oscar contenders and how they got here. Shortly, the Oscar fate of hundreds of feature and short documentary hopefuls will be decided during what is known as “preliminary voting” (December 8-12), when the 736 documentary branch members give each film they’ve seen a numbered score. This will yield the shortlist of 15, from which they will rank those films on a preferential ballot. The shortlist announcement will come on