No matter how many times the sharpest political scientists present data proving that the “Independent voter” category is largely a myth, some reporter will come out with an article somewhere larded up with quotes saying this or that candidate is toast because they can’t win ‘Independents.’ They are the myth that will not die, the elusive unicorns of politics, prancing around in sparkly woodlands in the easily-distracted heads of lazy reporters and academics.
So, one more time. There is no Santa Clause, no Easter Bunny, no tooth-fairy and there are no ‘independent voters.’ There are swing voters. There are political moderates. There are Reagan Democrats and other voters who sometimes vote for different parties. But over 90 percent of self-identified ‘independents’ lean Democratic or Republican, according to Alan I. Abramowitz, author of “The Disappearing Center: Engaged Citizens, Polarization, and American Democracy.” The term has little useful meaning, other than serving as a feel-good, catch-all category for Democratic and Republican voters who can’t bear to identify themselves as such.
Jamelle Bouie sheds light on the phenomenon in his American Prospect post, “New Name, Same Old Thing.”:

Among political scientists, it’s well known that the “independent voter” is a myth. When pressed, the large majority of voters lean Democratic or Republican and tend to vote like partisans, consistently supporting their party of choice. The only difference between a strong partisan and a “weak partisan leaner” is that the latter are reluctant–for whatever reason–to place themselves in one camp or the other…Over the last few years, this myth of the independent voter has taken hold among political journalists and others outside of academia.

Bouie provides a painful example of the delusion, which you can read if you want to at his link above, then has this to say about the so-called “Obama independents”:

“Obama Independents” fit the profile of a Democratic-leaning voter, who might defect from the party in GOP wave years, but for the most part chooses the name with “D” next to it when in the voting booth…There’s no need to hype Obama Independents as some new segment of the electorate, and indeed, the entire exercise is a little banal. Of course the Democratic presidential candidate needs to win a large majority of Democratic voters to win the presidency. That’s just how it goes.

The overwhelming majority of ‘independents’ are Republican and Democratic “leaners,” while swing voters and moderates will remain the more relevant categories for political analysis.