The use of standard costs can present a number of potential problems or disadvantages. Most of these problems result from improper use of standard costs and the management by exception principle or from using standard costs in situations in which they are not appropriate.

1. Standard cost variance reports are usually prepared on a monthly basis and often are released days or even weeks after the end of the month. As a consequence, the information in the reports may be so stale that it is almost useless. Timely, frequent reports that are approximately correct are better than infrequent reports that are very precise but out of date by the time they are released. Some companies are now reporting variances and other key operating data daily or even more frequently.

2. If managers are insensitive and use variance reports as a club, morale may suffer. Employees should receive positive reinforcement for work well done. Management by exception, by its nature, tends to focus on the negative. If variances are used as a club, subordinates may be tempted to cover up unfavorable variances or take actions that are not in the best interest of the company to make sure the variances are favorable. For example, workers may put on a crash effort to increase output at the end of the month to avoid an unfavorable labor efficiency variance. In the rush to produce output quality may suffer.

3. Labor quantity standards and efficiency variances make two important assumptions. First, they assume that the production process is labor-paced; if labor works faster, output will go up. However, output in many companies is no longer determined by hw fast labor works; rather, it is determined by the processing speed of machines. Second, the computations assume that labor is a variable cost. However, direct labor may be essentially fixed, then an undue emphasis on labor efficiency variances creates pressure to build excess work in process and finished goods inventories.

4. In some cases, a "favorable" variance can be as bad or worse than an "unfavorable" variance. For example, McDonald's has a standard for the amount of hamburger meat that should be in a Big Mac. A "favorable" variance would mean that less meat was used than standard specifies. The result is a substandard Big Mac and possibly a dissatisfied customer.

5. There may be a tendency with standard cost reporting systems to emphasize meeting the standards to the exclusion of other important objectives such as maintaining and improving quality, on-time delivery, and customer satisfaction. This tendency can be reduced by using supplemental performance measures that focus on these other objectives.

6. Just meeting standards may not be sufficient; continual improvement may be necessary to survive in the current competitive environment. For this reason, some companies focus on the trends in the standard cost variances - aiming for continual improvement rather than just meeting the standards. In other companies, engineered standards are being replaced either by a rolling average of actual costs, which is expected to decline, or by very challenging target costs.

In sum, managers should exercise considerable care in their use of a standard cost system. It is particularly important that managers go out of their way to focus on the positive, rather than just on the negative, and to be aware of possible unintended consequences.
Nevertheless standard costs are still found in the vast majority of manufacturing companies and in many service companies, although their use is changing. For evaluating performance, standard cost variances may be supplanted in the future by a particularly interesting development known as the balanced scorecard.