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Audit Quality and Using Other Experts' Work

Reporting and quality · 2 min read

Who audits the auditors?

Audit tells everyone else to check their work, so it had better check its own. ITAF requires audit work to be supervised and reviewed, and audit functions run a quality assurance and improvement program.

Supervision, work paper review, internal assessment, external assessment.
ElementWhat it involves
SupervisionSenior staff guide, monitor and review work during each audit
Work paper reviewEvery work paper reviewed; every finding and conclusion backed by evidence
Internal assessmentOngoing monitoring plus periodic self-assessment against the standards
External assessmentA periodic review by an independent, qualified outsider
FeedbackSurveys of auditees after audits; lessons learned
Performance measuresPlan completion, timeliness, recommendations implemented

Results of quality reviews go to the head of audit and, for external assessments, to the audit committee. Reviews are done by people who weren’t involved in the work.

Leaning on experts

IS auditors often rely on other people’s work: a penetration testing firm, a lawyer, an actuary, another audit team, or a service provider’s SOC report. That’s sensible, but ITAF requires the auditor to check them out first.

Check competence, independence, scope and quality of work, then decide whether to rely or add testing.
  • Competence: qualifications, certifications and experience in this exact area.
  • Independence and objectivity: any ties to the auditee, or a stake in the result? A vendor’s own consultants assessing their own product aren’t independent.
  • Scope: does the work cover the systems, period and risks the audit needs?
  • Quality: are the methods sound and the conclusions supported? The auditor may review the expert’s work papers.
  • Enough? Is it sufficient for the audit objectives, or are extra procedures needed?

Responsibility doesn’t move

Using an expert doesn’t transfer responsibility. The IS auditor’s name is on the conclusion, so the IS auditor has to be satisfied that the expert’s work is good enough.

Example. The audit relies on a penetration test commissioned by IT. The auditor checks the testing firm’s credentials and confirms it has no other contracts with IT that could bias it. The test left out the customer portal, which is in the audit’s scope, so the auditor plans extra testing for the portal.

The same thinking applies when external auditors rely on internal audit’s work, or internal audit relies on other assurance providers.

How the exam asks about it

If the question asks…The answer is usually…
First thing to consider before relying on an expert’s workTheir competence, independence and objectivity
The expert’s work doesn’t cover part of the scopePerform additional procedures
Who is responsible for the conclusions when an expert is used?The IS auditor
How audit work quality is ensured during an engagementSupervision and review of work papers
Purpose of an external quality assessmentAn independent check that the audit function meets the standards

In short

  • Audit quality comes from supervision, review of work papers, and a quality program with internal and external assessments.
  • External assessments are done periodically by an independent, qualified outsider.
  • Before relying on an expert's work, the auditor checks their competence, independence and objectivity.
  • The auditor also checks the expert's scope, methods and conclusions are good enough for the audit's needs.
  • Using an expert doesn't transfer responsibility: the IS auditor still owns the conclusions.
  • The same logic applies when external auditors rely on internal audit, or vice versa.

Exam traps

  • The auditor can't rely on an expert's report without reviewing its scope and quality.
  • A vendor's own consultants assessing their product aren't independent.
  • Using an expert doesn't reduce the auditor's responsibility for the opinion.
  • Quality reviews should be done by people who weren't involved in the work.

Slides

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CISA · Domain 1 · Reporting and quality

Audit Quality and Using Other Experts' Work

How the audit function makes sure its own work is good, and what an auditor must check before relying on someone else's work.

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