The Investigation of Cost Variances: A Fuzzy Set Theory Approach*

ABSTRACT In a standard costing system, deviations (variances) of actual cost from standard cost should be investigated in order to help management identify the causes of the variances and who is responsible for them before corrective actions are taken. In reality, however, actual cost rarely equals standard cost and so many variances occur that it is impractical and uneconomical to investigate all of them. These two conflicting factors—the necessity of investigating cost variances and the impracticality of investigating all the variances—present management with the problem of deciding which variances to investigate. In this paper a model, based on fuzzy set theory, for the cost‐variance investigation is proposed and applied to an actual investigation problem faced by a manufacturing company.