The four contributors to this blog--Drs. Michael Bitzer, Christopher Cooper, Whitney Ross Manzo, and Susan Roberts--recently had their research on North Carolina's Unaffiliated voters published in the journal Social Science Quarterly.
Using data from North Carolina's voter registration and history files along with public opinion data from the Meredith College Poll, this academic study points to the idea that Unaffiliated registrants are not simply shadow partisans but, on average, are distinct from the two major parties in terms of demographics, political behavior, and political attitudes.
The study concludes that voters who eschew party labels are best understood as unmoored voters--often hovering close to their ideological docks but with no institutional constraint to keep them from drifting as the political tides shift.
You can find a link to the full study (in PDF) here at the Social Science Quarterly website.