AUD, Auditing and Attestation

Sources for Planning for and Using the Work of Others

Last reviewed 2026-09-14

The standards and authorities behind PocketCPA's AUD lessons on Planning for and Using the Work of Others. The topic rests on AU-C 600.

About this topic

Auditors rarely work alone. Somebody else has often already done part of the work, or knows something the audit team does not, and the standards say when that work can be leaned on.

In every case the auditor evaluates the other party's competence and objectivity and remains responsible for the audit opinion.

Key points

• The auditor may use the work of internal auditors if they are objective and competent, but must still direct, supervise, and review.
• A specialist's work may be used when the auditor lacks expertise in a particular area, but the auditor remains responsible for the conclusion.
• The component auditor performs work on a component of a group audit; the group engagement partner must evaluate the sufficiency of that work.
• Other auditors' reports may be referenced in the group auditor's report under specific conditions.

What the lessons cover

1. The internal audit function (AU-C 610)
2. The auditor's specialist (AU-C 620)
3. Group audits
4. Planning: deciding that somebody else is needed (AU-C 300, AU-C 330, AS 2101)
5. The PCAOB framework: three specialist categories and a supervised chain
6. Using the work of others in an ICFR audit (AS 2201.16 through .19)
7. Reporting: when a report may, must, or must not name someone else

Authoritative references

Where these requirements sit in the literature. Each entry names the standard, then breaks it out paragraph by paragraph.

• AU-C 610, the internal audit function.
  • .15 the three-part gate: organizational status and relevant policies supporting objectivity, competence, and a systematic and disciplined approach including quality management.
  • .18 sole responsibility, all significant judgments with the external auditor, and more direct work as judgment and assessed risk rise.
  • .24 objectivity tied to organizational status, plus audit procedures on the work used as a whole, including reperforming some of it.
  • .26 is the only prohibition on direct assistance: the internal auditor lacks the necessary objectivity, or lacks the necessary competence, for the proposed work. .27 makes the threats-and-competence evaluation, the assessed risk of material misstatement and the amount of judgment involved factors in setting both the work assigned and the direction, supervision and review; .29 requires the auditor to remain sufficiently involved given sole responsibility for the opinion; .31 carries the direction, supervision and review itself. The four-category bar familiar from ISA 610 (Revised 2013) paragraph 30 is not in GAAS, which the AU-C 610 appendix states expressly.
  • The separate bar on using the function's work at all where objectivity is unsupported is carried at standard level.
• AU-C 620, the auditor's specialist.
  • .06 scope: expertise in a field other than accounting or auditing; a management's specialist goes to AU-C 500 and an accounting or auditing expert such as a tax partner or engagement quality reviewer is outside the section.
  • .09 evaluate competence, capabilities, and objectivity, inquiring about interests and relationships for an external specialist.
  • .12 evaluate the adequacy of the work: findings and conclusions, significant assumptions and methods, and the relevance, completeness and accuracy of source data.
  • .14 no reference in a report with an unmodified opinion; where reference is required by law or regulation or is relevant to a modification, the report must state it does not reduce the auditor's responsibility.
  • The requirement to agree the nature, scope and objectives of the work is carried at standard level.
• AU-C 500 covers a management's specialist at .09: evaluate competence, capabilities and objectivity, obtain an understanding of the work, and evaluate its appropriateness as evidence for the relevant assertion. As amended by SAS No. 142 it separately covers information from an external information source, evaluated for relevance and reliability including the nature and authority of the source.
• AU-C 600, group audits.
  • .11 a significant component is either of individual financial significance or likely, by its specific nature or circumstances, to include significant risks of material misstatement of the group financial statements.
  • .14 acceptance and continuance: whether the team can reasonably expect to obtain sufficient appropriate audit evidence, with decline, disclaimer or withdrawal where an unresolvable restriction on a material component makes the effect pervasive.
  • .22 and .33 component materiality set by the group team and required to be lower than group materiality, with .22 adding the duty to understand the component auditor's compliance with ethical requirements, particularly independence, and professional competence.
  • .25 the conditions on making reference: same, acceptable or reconciled framework; an audit under the applicable auditing standards; a report not restricted as to use; and the group engagement partner satisfied as to that auditor.
  • .51 the scope ladder: audit using component materiality, audit or targeted procedures, or group-level analytical procedures.
• AU-C 300.07 and .08 carry the overall audit strategy, with the number and locations of components in scope and deploying experienced personnel and specialists to higher-risk areas in the nature, timing and extent of resources. AU-C 330 treats engaging specialists, assigning more experienced personnel, increasing supervision and adding unpredictability as overall responses to financial-statement-level risks, distinct from assertion-level further audit procedures.
• AS 1210, the auditor-engaged specialist.
  • .03 knowledge, skill and ability.
  • .04 no use of one who lacks it.
  • .05 objectivity.
  • .06 a documented understanding of the work.
  • .09 review and evaluation of the specialist's report, scaled by significance, risk and ability (.10).
  • .11 remediation of impaired objectivity.
  • .12 additional procedures on contradiction.
• AS 1201, supervision.
  • .03 and .04 the engagement partner's responsibility, extending to team members outside the partner's firm.
  • .05 and .06 the supervisory activities and their extent.
  • .08 through .13 the lead auditor's written supervision of other auditors.
  • .14 and .15 multi-tiered audits.
  • Appendix C, at .C2, .C3, .C5, .C6 and .C7, the auditor-employed specialist.
• AS 1105, Appendix A, the company's specialist.
  • .A3 knowledge, skill and ability.
  • .A4 the company's ability to affect the specialist's judgments.
  • .A5 and .A7 evidence scaled to significance and risk.
  • .A8 data, assumptions and methods.
  • .A9 relevance and reliability.
  • .A10 contradiction.
  • .A6 locates the "do we need specialized skill" determination in AS 2101.16 through .17.
• AS 2201.16 through .19, using the work of others in an ICFR audit.
  • .16 the intended extent of use, with AS 2605 applying in an integrated audit.
  • .17 a population reaching internal auditors, company personnel in addition to internal auditors, and third parties working under the direction of management or the audit committee.
  • .18 competence and objectivity, applying AS 2605.09 through .11 to internal auditors and the principles underlying them to others, subject to two absolute floors.
  • .19 the risk associated with the control.
• AS 1301.10 requires communicating the planned extent of that use, and the names, locations and planned responsibilities of other accounting firms, to the audit committee.
• AS 1206, Dividing Responsibility for the Audit with Another Accounting Firm governs a lead auditor making reference to a referred-to auditor's report on one or more business units. AS 3101.18 requires explanatory language for that division without affecting the opinion. AS 2101.06A through .06C address serving as the lead auditor, and AS 2101.16 through .17 require determining whether specialized skill or knowledge is needed. AS 1206, AS 2605 and AS 2101 are cited at standard level. The paragraph references to AS 2605.09 through .11 and AS 2101.06A through .06C rest on cross-references inside AS 2201.18 and AS 3101 footnote 24, not on those standards' own retrieved text.

How PocketCPA uses these sources

Every lesson is written in original words and cites the paragraph each rule comes from. No standard's text is reproduced. How lessons and questions are written and checked is set out in our methodology.

See also

• Sources for every AUD topic
• Free AUD sample questions
• The CPA exam glossary