The New York Times  asked my appraisal firm, Miller Samuel  to research the “flipping” phenomenon in Manhattan, which is noted for its high housing prices and dominance of co-ops. So much has been written about real estate speculation over the past several months in other markets like Florida but no one has quantified the phenomenon in Manhattan.
The idea here is that a real estate market with rampant flipping (we define a flip as re-selling a property within 18 months) as a danger sign for future price volatility. A market based on flips is ultimately doomed, like a fee simple ponzi scheme with a foggy end point. In fact, developers in Miami encourage flips  and have sales agents in place (for a 2nd commission on the same property) to sell your unit for you. Easy money.
Our study, as noted in the New York Times article on October 2, 2005 , determined that property flips, after controlling for typical moves like job transfers or changes in income, was about 3% of all sales activity, far less than the national average of 23% compiled by the NAR. [Matrix]. 
When electricians and health care workers are quitting solid secure jobs to flip real estate, then its time to get out. Fortunately, this is not happening in Manhattan.
So in some respects, one could consider that high housing prices and difficulties with co-ops in Manhattan, actually makes the housing market there less volatile.