claaarky - 11:52 am on Sep 21, 2012 (gmt 0)
I have a suspicion that the actual correlation between those shorter pages is that people like them more than your longer pages. It would be interesting to see how the stats for those pages compare to the stats for the 150+ word pages (time on page, exit rate, bounce rate).
My view is that Panda doesn't 'look' at your content, it judges the metrics of a page against the metrics of other pages and sites. If you have a lot of pages that measure up very badly (people don't like them) compared to most other sites in your niche, I think that's how Google can tell you have low quality content and Panda then demotes you appropriately.
I don't think there is a pattern to how much text you need on a page, no secret formula, no definition of thin/shallow content. It's a popularity competition and your visitors do the voting (reflected in your user metrics). Google just counts the votes and demotes any pages that are clearly much more unpopular than the majority.
The problem is we don't know how the voting is going for other sites, so even if we can tell from our metrics that we're becoming more popular, we don't know how popular we need to be to get out of Panda.
The question is what do we need to do to become much more popular. I think trust is very powerful. I personally will cut a well known site much more slack than one I haven't heard of, and that means their user metrics will look much better even if their website isn't that great and suffers from many of the things we think Panda is out to get.