The classification of expenses by variability should begin with a carefull study of each 
this expense in the responsibility center under consideration. The purpose of his study is to identify those expenses that contain only "pure” fixed or variable components.When the fixed and variable expenses are separately identified, the remaining accounts can be viewed as semivariable. Each expense account determined to be semivariable must be analyzed to identity is fixed and variable components.The methods discussed in this section are based on the assumption that semivariable expenses can be analyzed and their fixed and variable components be reliably estimated. These estimates (i.e., the flexible budget formulas) involve two steps: (1) analysis of each expense followed by (2) managerial judgment to move from the analyzed “historical figures" to realistic flexible amounts.