Nate Cohn of the New York Times bucks the prevailing Democratic meme that if they spend enough money and use the incredible Obama analytics they'll change the electorate. I've participated in a bunch of GOTV efforts, all of which are pretty much walking precincts and making phone calls. GOTV can certainly help, especially if the top of the ticket isn't a Presidential election. That said, no matter how brilliant your analytics are you can't get people who don't want to talk to you to pick up the phone or answer the door. You can't get those you contact to listen to your pitch if they have no interest.
California voter rolls list how many of the past five elections someone has voted in. You want to make sure 4s and 5s, people who've voted in 4 of 5 or 5 of 5 elections, get out to vote. Yet I've had Republican 5s, people we know we're going to get, take my literature and get rid of me. You're sure you have them, but they don't act like it. If there was a magical pitch to get 1s and 2s to the polls, they wouldn't be 1s and 2s. You aren't going to get a lot of them in a mid-term. Cohn is right. You should try to turn out 1s and 2s but you should spend more time trying to convince 4s and 5s who lean Republican but might be open to voting Democratic.