A second step is to then examine the effect of using overtime to produce some units. Overtime may be used to produce the units by reducing the number of employees for the month and then producing the needed units on overtime. A comparison of the total costs will show which result is lower. Choose the lower solution for the month and proceed to the next month. This result helps contribute to a low total cost solution.
Students tend to try to use subcontracting without fully realizing the effect on cost.
The use of a spreadsheet is a natural way to analyze the interactions. Students can see what happens when each variable is changed. They will normally approach the minimum cost solution through extensive trial and error. The spreadsheet has proven to be an excellent tool for exploring the variables encountered in an aggregate scheduling problem. By changing the initial conditions and constraints, the problem can be used to simulate a variety of aggregate scheduling problems and the strategies employed to deal with these complex situations.