Multiple Causes of Variances
Managers must not interpret variances in isolation of each other. The causes of variances
in one part of the value chain can be the result of decisions made in another part of the
value chain. Consider an unfavorable direct materials efficiency variance on Webb’s production
line. Possible operational causes of this variance across the value chain of the
company are as follows:
1. Poor design of products or processes
2. Poor work on the production line because of underskilled workers or faulty machines
3. Inappropriate assignment of labor or machines to specific jobs
4. Congestion due to scheduling a large number of rush orders from Webb’s sales
representatives
5. Webb’s suppliers not manufacturing cloth materials of uniformly high quality
Item 5 offers an even broader reason for the cause of the unfavorable direct materials efficiency
variance by considering inefficiencies in the supply chain of companies—in this
case, by the cloth suppliers for Webb’s jackets. Whenever possible, managers must
attempt to understand the root causes of the variances.