Short ETFs

I recently renewed my subscription to Barron's, after some years away.  My initial impression is that it is a good publication.  How do I judge that?  It's largely useless but every issue has a few nuggets worth thinking about.  That translates to good because most publications don't even have a few nuggets.  One column which has had a few interesting pieces is "ETF Focus" by Brendan Conway.  A recent post discussed research showing that flows into short ETF's is, contrary to what one might think, actually an indicator that stocks will go up.  There are two explanations for this:  (1) these ETF's are being used by sophisticated, bullish traders who use them to hedge increasing long positions; and (2) these ETF's are used by impatient individual investors who are generally wrong about market direction.  The difficulty here is that it is not possible to definitively know what the makeup of these ETF's is in terms of whether they are predominantly purchased by group 1 or group 2 above.  Still, it is an interesting finding (assuming the research is even right).  One might extend the finding to say that increasing flows into these funds on a month to month basis might indicate general economic improvement.