ICv2 has a nice interview with Mark Siegel, which looks at the metrics of how getting a book nominated for a major award affects sales:

The first list [of First Second graphic novels] that came out in May went to reprint before the release dates on all six titles. And it’s something pretty similar with the second list. But obviously American Born broke away from the pack because of the National Book Award nomination. So right now the back orders are going into negative, which is all good news. We’re happy with it. I’m feeling that I’m building a collection [that will create a strong backlist]. People don’t talk that much about backlist anymore in publishing, like it’s an antiquated thing, but that’s certainly not the case with us and I think for graphic novels in general. One of the things the big publishing houses have discovered over time is the backlist of a good graphic novel will just go on and on and on.