Stepping Stone Methods :

This is a procedure  of determining the optimal if any for improving  each  of the non basic  variables  in terms of the objective function. To determine  this  potential each of the non basic  variables ( Empty cells ) is consider one by one. For  each  such well  we find  out as to what  effect on  the total cost  would  be if  one unit is assigned to this  cell. With  this information  then we come  to know  whether  the solution  is optimal  or not. If not we  improve  that solution. To  understand  it we  refer to the  table a side which  is a reproduction of the  table above  containing the  initial basic  solution obtained by NW corner rule.

 In the  above table there  are four empty cells  BD, CD, AF, BF,

The  rule for  testing  the optimality  is if none  of the empty  cell has a positive  opportunity  cost the solution is optimal. And if  one ( or more ) of  the empty  cell have  a positive  opportunity  cost the  solution is not  optimal  and calls for revision. We  concentrate only on the cells  that  have  positive  opportunity  cost and would  select the one with  the highest  value.