Procedure Design, Evidence Sources, and Audit Program Documentation

Design procedures, evidence sources, nature, timing, extent, and audit program documentation.

Procedure design is the bridge between risk assessment and evidence. A procedure should state what will be done, to what population or item, for what period, using what evidence source, and which risk, assertion, or criterion it addresses.

The practical task is to write procedures that are specific enough to perform and strong enough to answer the risk. Vague procedures create weak evidence even when the general idea is correct.

What This Lesson Covers

This lesson focuses on how to:

  • identify evidence sources that match the risk, assertion, or criterion
  • design procedures using nature, timing, and extent
  • distinguish weak procedure wording from performable procedure wording
  • evaluate whether a proposed procedure actually addresses the identified risk
  • document procedures in an audit program or assurance work plan
  • separate procedure design from evidence evaluation after the work is performed
  • revise procedures when the risk, evidence source, or population changes

A Strong Procedure Sentence

A procedure should be specific enough that another practitioner could perform it. It should also explain why the work is being done.

Component Question Weak wording
Action What will be done? “Check revenue.”
Evidence source What document, system, person, or external source will be used? “Look at support.”
Population Which items or period are covered? “Some invoices.”
Assertion or criterion What risk does the procedure address? No link to occurrence, completeness, valuation, compliance, or other criterion.
Extent How many items or what scope? No sample size, threshold, or selection basis.
Timing When is the work performed? No period-end or interim consideration.
Expected output What evidence or conclusion should result? No explanation of what would support or contradict the risk.

A stronger sentence might say: “Select recorded revenue transactions for the two weeks before and after year end and agree each item to the customer order, delivery evidence, invoice, and subsequent collection to test occurrence and cut-off.” That wording identifies the action, population, evidence, timing, and purpose.

Nature, Timing, And Extent

Procedure design changes with risk. Higher risk usually requires more persuasive evidence, more precise timing, or broader extent.

Dimension Meaning Risk response
Nature Type and quality of procedure and evidence source. Higher risk usually needs more persuasive evidence, such as external confirmation or reperformance.
Timing When the procedure is performed. Higher period-end risk may require work closer to or after year end.
Extent Quantity, coverage, or depth of work. Higher risk may require larger samples, lower thresholds, or broader coverage.

Nature, timing, and extent should not be generic labels. The answer should state what changes. For example, if collection risk is high, confirming more receivables near year end may be stronger than relying only on interim analytical procedures.

Evidence Source Reliability

Evidence source affects procedure strength. The practitioner should consider independence, objectivity, directness, relevance, and reliability of the system or process that produced the evidence.

Evidence source Reliability consideration
External confirmation Often persuasive when received directly by the practitioner.
Third-party document Stronger than internally generated evidence if authentic and relevant.
System report Depends on IT controls, report parameters, and data completeness.
Management inquiry Useful for understanding but usually weak alone.
Observation Shows a process at a point in time but not necessarily throughout the period.
Reperformance Persuasive for recalculation or control operation when population selection is appropriate.
Analytical procedure Useful when relationships are predictable and data is reliable.

Inquiry is rarely enough for a high-risk conclusion. It should usually be corroborated with inspection, confirmation, recalculation, reperformance, observation, or data testing.

Procedure Examples By Risk

Risk or assertion Weak procedure Stronger procedure
Revenue occurrence Review sales. Select recorded sales near year end and agree to customer order, delivery or service evidence, invoice, and subsequent collection.
Payables completeness Inspect invoices. Search subsequent payments and unmatched receiving reports after year end for unrecorded liabilities.
Inventory valuation Discuss inventory with management. Inspect ageing reports, compare cost to subsequent sales or replacement cost, and evaluate write-down assumptions.
Control operation Ask whether review was performed. Inspect evidence of review for selected periods, verify reviewer competence, and follow up exceptions.
Compliance with grant terms Read grant agreement. Map each key term to evidence, inspect supporting records, and test exceptions against the reporting period.
System access risk Ask IT about access. Obtain user access listing, compare to HR records, inspect approvals, and test removal of terminated users.

The stronger procedures use evidence that directly responds to the risk. They also define the population and action clearly enough to document in a work plan.

Audit Program Documentation

An audit program or assurance work plan should show the logic between risk and procedure. The work paper should not be a checklist detached from the case facts.

Work plan field Why it matters
Risk or objective Shows why the procedure is being performed.
Assertion or criterion Links the procedure to what could go wrong.
Procedure wording Gives clear instructions for the work.
Population and extent Defines coverage and selection basis.
Timing Shows whether interim, year-end, or subsequent work is needed.
Evidence source Identifies the records, reports, confirmations, or observations to use.
Conclusion field Forces the practitioner to evaluate results instead of only signing off.

If a procedure is changed during the engagement, the work plan should explain the reason. A change may be caused by control failures, new risks, unreliable reports, client delays, or unexpected exceptions.

Design Versus Evaluation

Procedure design happens before evidence is obtained. Evidence evaluation happens after the work is performed.

Stage Practitioner question
Design Will this procedure obtain evidence that responds to the risk?
Performance Was the procedure performed as planned and documented?
Evaluation Is the evidence sufficient and appropriate, and what does it mean?
Response Is more work, correction, communication, or report modification needed?

This distinction matters in case writing. If the problem is a weak proposed procedure, redesign it. If the problem is an exception found during testing, evaluate the evidence and state the next action.

Application Framework

Step Question Output
1. Risk What risk, assertion, or criterion needs evidence? Procedure objective.
2. Evidence source Which source would be persuasive and available? Evidence source.
3. Nature What action should the practitioner perform? Procedure action.
4. Timing and extent When and how much work is needed? Timing and coverage.
5. Documentation How should the procedure appear in the audit program or work plan? Clear procedure wording.

Use this framework when asked to design, critique, improve, or document a procedure.

Common Pitfalls

Pitfall Correction
Writing vague procedures. Specify action, evidence source, population, timing, extent, and assertion or criterion.
Choosing a procedure that does not answer the risk. Link every procedure to the risk it addresses.
Treating inquiry as enough for high-risk areas. Corroborate with inspection, confirmation, reperformance, or independent evidence.
Ignoring report reliability. Test system reports and IT controls when reports are used as evidence.
Confusing design with evaluation. Design procedures first; evaluate sufficiency and appropriateness after evidence is obtained.

Key Takeaways

  • Procedure design should be risk-linked and specific enough to perform.
  • Nature, timing, and extent change as assessed risk changes.
  • Evidence reliability depends on source, independence, objectivity, directness, and system reliability.
  • A strong procedure names the action, evidence source, population, period, extent, and assertion or criterion.
  • Procedure design is different from evidence evaluation after the work is performed.
Revised on Monday, June 15, 2026