It's a bit odd to see how controversial the thing seemed to be this year. There were dismissive articles about NaNoWriMo and, unsurprisingly, a number of people leaped to its defense in response. Some of the criticisms seemed to be along the lines of Stop Having Fun, Guys and a curious and unproven allegation that the slush piles of December are glutted with NaNovels.
But there was also the concern, and I think it one that needed to be addressed, that people who fall short on NaNoWriMo wind up getting mauled by their internal gremlins, the ones who threw everything at them to get them to stop and then turned around and kicked them for not succeeding. (Nasty buggers, those gremlins. Every word I write for the world to read is a tiny victory against them.)
This year I almost didn't make it. Part of it was perhaps simple overconfidence--I'd done it five years running, surely I know how to handle this, right? There was also the fact that I spent the month doing some time-consuming online work in order to keep my mortgage paid and my lights on, since my unemployment insurance has completely run out. I never hit the purple this-is-where-you-should-be-by-now line on the NaNo Stats page until the very last day. And yet I persisted, in part out of stubborn pride but also because, honestly, as unpublishable and useless a mess as I ended up with, I wound up enjoying the time I was spending with these characters and wanting to see how it worked out for them.
There are undoubtedly quite a few souls out there who didn't make it to the finish line, who got overwhelmed, who fell so far behind they saw no way of making it in time and didn't see the point of persisting. Some people throw their hands up and say "Ah, well, maybe next year" but others wind up feeling that if they can't even squeeze out fifty thousand words of crap by the deadline, what the hell good are they?
Falling short on NaNoWriMo does not make you a failure as a writer. It might just mean that you had other priorities, that the story wasn't holding your interest or, more than likely, that the thirty-day-deadline method doesn't work for you as a writer.
There are two ways you can do the math, when you look at your final wordcount.
Subtract your wordcount.
This is the number you fell short.
This is the way most people are inclined to do it, even as it makes them miserable.
Consider this equation:
Take your wordcount.
This is the number you came out ahead of where you would have been otherwise.
I much prefer the latter to the former.