Managers and management accountants use variances to evaluate performance after decisions are implemented, to trigger organization learning, and to make continuous improvements. Variances serve as an early warning system to alert managers to existing problems or to prospective opportunities. When done well, variance analysis enables managers to evaluate the effectiveness of the actions and performance of personnel in the current period, as well as to fine-tune strategies for achieving improved performance in the future. Concepts in Action: Can Chipotle Wrap Up Its Materials-Cost Increases? shows the importance of direct-cost variance analyses to the fast casual dining giant.
To interpret variances correctly and to make appropriate decisions, managers need to understand the multiple causes of variances. They also must not interpret a variance in isolation. A variance in one part of the value chain may result from decisions made in the same or 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 are shown below:
Item 5 offers an even broader reason for the unfavorable direct materials efficiency variance—inefficiencies in the supply chain of cloth suppliers for Webb’s jackets. Whenever possible, managers must attempt to understand root causes of variances.