If you are concerned that having duplicate content could be a factor in the Panda algo, John Mueller from Google has confirmed that duplicate content and Panda are two separate and independent things.

Marie Haynes raised the question with John Mueller, and whether duplicate content could have an impact on Panda.

Duplicate content isn’t actually a penalty, but a filter, and while Google will choose one of the duplicated URLs to display if the webmaster doesn’t give any signals of which URL to rank in the search index, it generally doesn’t cause any negative repercussions with the site, except in one circumstance… if it is a site only publishing duplicate content without adding value to those pages.

So in this regard, it isn’t surprising that duplicate content would have no impact on other aspects of the algo, including Panda.

But while the two issues aren’t directly related, if you are cleaning up a site for algo reasons, it makes sense that while you are buffing up the quality of content on the site, you might as well get a handle on the duplicate content as well, to simply to have more quality pages to rank that aren’t similar enough to other pages on the site to be flagged as duplicate.