SAS No. 20 Using the Work of an Expert


Issued by Auditing Standards Committee in Taiwan on 16 November, 1990.


When using the work performed by an expert, the auditor should obtain sufficient appropriate audit evidence that such work is adequate for the purposes of the audit.

“Expert” means a person or firm possessing special skill, knowledge and experience in a particular field other than accounting and auditing.

An expert may be:

  • Engaged by the entity;
  • Engaged by the auditor;
  • Employed by the entity; or
  • Employed by the auditor.

The auditor may need to obtain audit evidence in the form of reports, opinions, valuations and statements of an expert for situations such as the following:

  • Valuations of certain types of assets, for example, land and buildings, plant and machinery, works of art, and precious stones.
  • Determination of quantities or physical condition of assets, for example, minerals stored in stockpiles, underground mineral and petroleum reserves, and the remaining useful life of plant and machinery.
  • Determination of amounts using specialized techniques or methods, for example, an actuarial valuation.
  • The measurement of work completed and to be completed on contracts in progress.
  • Legal opinions concerning interpretations of agreements, statutes and regulations.

When determining the need to use the work of an expert, the auditor would consider:

  • The engagement team’s knowledge and previous experience of the matter being considered;
  • The risk of material misstatement based on the nature, complexity, and materiality of the matter being considered; and
  • The quantity and quality of other audit evidence expected to be obtained.

When planning to use the work of an expert, the auditor should evaluate the professional competence of the expert. This will involve considering the expert’s:

  • Professional certification or licensing by, or membership in, an appropriate professional body; and
  • Experience and reputation in the field in which the auditor is seeking audit evidence.

The auditor should evaluate the appropriateness of the expert’s work as audit evidence regarding the assertion being considered. This will involve evaluation of whether the substance of the expert’s findings is properly reflected in the financial statements or supports the assertions, and consideration of:

  • Source data used;
  • Assumptions and methods used and their consistency with prior periods; and
  • Results of the expert’s work in the light of the auditor’s overall knowledge of the business and of the results of other audit procedures.

When considering whether the expert has used source data which is appropriate in the circumstances, the auditor would consider the following procedures:

  • Making inquiries regarding any procedures undertaken by the expert to establish whether the source data is relevant and reliable.
  • Reviewing or testing the data used by the expert.

If the results of the expert’s work do not provide sufficient appropriate audit evidence or if the results are not consistent with other audit evidence, the auditor should resolve the matter. This may involve discussions with the entity and the expert, applying additional audit procedures, including possibly engaging another expert, or modifying the auditor’s report.

When issuing an unmodified auditor’s report, the auditor should not refer to the work of an expert.

If, as a result of the work of an expert, the auditor decides to issue a modified auditor’s report, in some circumstances it may be appropriate, in explaining the nature of the modification, to refer to or describe the work of the expert (including the identity of the expert and the extent of the expert’s involvement). In these circumstances, the auditor would obtain the permission of the expert before making such a reference. If permission is refused and the auditor believes a reference is necessary, the auditor may need to seek legal advice.

Effective date

This Statement is effective for audit of financial statements with fiscal years ending on or after 31 December, 1990.

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