控制（Controlling）

(b) Controlling variable costs
The first step in the process of controlling costs is to measure actual costs. The second step is to calculate variances that show
the difference between actual costs and budgeted or standard costs. These variances then need to be reported to those
managers who have responsibility for them. These managers can then decide whether action needs to be taken to bring actual
costs back into line with budgeted or standard costs. The operating statement therefore has a role to play in reporting
information to management in a way that assists in the decision-making process.
The operating statement quantifies the effect of the volume difference between budgeted and actual sales so that the actual
cost of the actual output can be compared with the standard (or budgeted) cost of the actual output. The statement clearly
differentiates between adverse and favourable variances so that managers can identify areas where there is a significant
difference between actual results and planned performance. This supports management by exception, since managers can
focus their efforts on these significant areas in order to obtain the most impact in terms of getting actual operations back in
line with planned activity.
In control terms, variable costs can be affected in the short term and so an operating statement for the last month showing
variable cost variances will highlight those areas where management action may be effective. In the short term, for example,
managers may be able to improve labour efficiency through training, or through reducing or eliminating staff actions which
do not assist the production process. In this way the adverse direct labour efficiency variance of ￡252, which is 7·3% of the
standard direct labour cost of the actual output, could be reduced.
Controlling fixed production overhead costs
In the short term, it is unlikely that fixed production overhead costs can be controlled. An operating statement from last month
showing fixed production overhead variances may not therefore assist in controlling fixed costs. Managers will not be able to
take any action to correct the adverse fixed production overhead expenditure variance, for example, which may in fact simply
show the need for improvement in the area of budget planning. Investigation of the component parts of fixed production
overhead will show, however, whether any of these are controllable. In general, this is not the case2.
Absorption costing gives rise to a fixed production overhead volume variance, which shows the effect of actual production
being different from planned production. Since fixed production overheads are a sunk cost, the volume variance shows little
more than that the standard hours for actual production were different from budgeted standard hours3. Similarly, the fixed
production overhead efficiency variance offers little more in information terms than the direct labour efficiency variance. While
fixed production overhead variances assist in reconciling budgeted profit with actual profit, therefore, their reporting in an
operating statement is unlikely to assist in controlling fixed costs.