Lean Accounting
The numerous changes in structural and procedural activities that we have described for a lean firm also change traditional cost management practices. The traditional cost management system may not work well in the lean environment. In fact, the traditional costing and operational control approaches may actually work against lean manufacturing. Standard costing variances and departmental budgetary variances will likely encourage overproduction and work against the demand-pull system needed in lean manufacturing. For example, emphasis on labor efficiency by comparing actual hours used with hours allowed for production encourages production to keep labor occupied and productive. Similarly, emphasis on departmental efficiency (e.g., machine utilization rates) will cause non-bottleneck departments to overproduce and build work-in-process inventory. Furthermore, we already know from our study of activity-based costing that in a multiple-product plant, the use of a plant-wide overhead rate can produce distorted product costs relative to focused manufacturing assignments or activity-based assignments. Distorted product costs can signal failure for lean manufacturing even when significant improvements may be occurring. To avoid obstacles and false signals, changes in both product-costing and operational control approaches are needed when moving to a value-stream-based lean manufacturing system8.
8 Much of the material on lean accounting is based on two sources :Frances A. Kennedy and Jim Huntzinger, “Lean Accounting: Measuring and Managing the Value Stream,” Cost Management (Sep./Oct. 2005): pp.31-38, and Brian Maskel and Bruce Baggaley, Practical Lean Accounting (New York: Productivity Press, 2004)