Kalia, thats what forecasters do, ain't it?  You see weather-men do the same, You even see engineers forecast the life-span of a cerain bridge they built or doctors forecast the life-span of cancer patients in their last stages...And hell, they do get their estimates wrong too.  With weathermen, what about all those ice-storms and rains that have missed NYC completely when we watch on TV the night before about the impending doom coming our way?  What about the engineers who said the Brooklyn Bridge would last for 30 years after completion...Its 130 years old now and still shows no sign of coming down!  How about the docs who said to Lance Armstrong, a cancer patient that his bike-racing career is over and should be happy just to survive the treatment...But yet he won the Tour de France 7 times after that? 

Every field has guesswork and estimates involved in it and economics is just the same.  If definite answers through definte proof were present we'd be in a perios of continuous uptrend in the Business Cycle or a constant Bublle that never bursts.  In dismal scientist talks, we'd have achieved the Holy Trinity.  The Holy Trinity = Low Unemployment, Low Inflation, High Economic Growth. 

Listen, Man may step foot on Mars someday, but even then the Holy Trinity will still not be achieved.