e relationships exist, but rather are the relationships consistent enough to predict rates in a rapidly changing world.L. Douglas Lee, Chief Economist at HSBC Securities, best sums up both current and past theory. " These various road maps or rules that we use are valid at times but what you always have to remember is that the U. S. economy is a very dynamic creature and things don't remain fixed. What works at one point in terms of understanding inflation may not work in another, but then may change and work again. The trick for policy makers is to remain flexible and to recognize when their old assumptions are no longer working." Policy makers, and all of us , have to stay on top of things so we do not use the old map on a new road.(Stevenson, April 11,1999)Today's realities do not necessarily fit yesterday's models....