In a big industry  the numbers  of factors influencing a decision have increased situation has  become big  and complex because these factors interact with  each other in  complicated fashion. There is thus great uncertainty about the outcome  of interaction of  factors like technological environmental competitive etc. For instance consider a factory  production schedule which  has to  take into account.
a.	 Customer demand.
b.	 Requirements  of raw  materials.
c.	 Equipment capacity  and possibility  of equipment failure and
d.	 Restrictions on  manufacturing process