Many companies experience regular surges in demand during continual time periods with fixed peri- od length,which is referred to as"Hockey stick"phenomenon.In the early stage of a time period,the de- mand is low,while the demand is high at the end of the time period.This phenomenon is quite prevalent in supply chains,which puzzles many managers.In the traditional viewpoint,the phenomenon is due to the fact that salespeople are regularly measured.However,this paper does not agree on above viewpoi...