Sector rotation is a matter of time frames.  The TV pundits use the term whenever the daily trade is to sell one group and buy another.  The news story is measured from one day to another. The problem for investors, and perhaps even traders, is that these very short-term moves must be guessed in advance.  This is not very helpful for system traders.  One needs time to read a new signal. The Fundamental Problem Last week we enjoyed a day back in the classroom -- a guest lecture invitation.  It is a good opportunity to think about one's message.  What can one say to a group of very intelligent and eager young students? Here was part of our message. Many trading models take data from period "A" and forecast period "B".  The time frame for these periods can range from seconds to months.  Each model gives a ...