The Five Shall Paragraphs

0.1 What is true

The obligation side of the standard is empty of quantities. Paragraphs 10 to 14 require the auditor to determine materiality, to determine performance materiality, to revise both when the audit turns up information that would have changed them, and to document the amounts and the factors considered. They do not say how to get to a number.

0.2 What is false

The standard does name figures. It names them in guidance, explicitly, as worked examples. This is the paragraph the whole document turns on.

CAS 320, paragraph A8 Application material Periods ending on or after 14 Dec 2010

Determining a percentage to be applied to a chosen benchmark involves the exercise of professional judgment. There is a relationship between the percentage and the chosen benchmark, such that a percentage applied to profit before tax from continuing operations will normally be higher than a percentage applied to total revenue. For example, the auditor may consider five percent of profit before tax from continuing operations to be appropriate for a profit-oriented entity in a manufacturing industry, while the auditor may consider one percent of total revenue or total expenses to be appropriate for a not-for-profit entity. Higher or lower percentages, however, may be deemed appropriate in the circumstances.

Three hedges in one paragraph: "may consider", "For example", and "Higher or lower percentages, however, may be deemed appropriate". Quoted again in its home context in section 02.

A8 is about as far from a rule as authoritative-adjacent text gets, and it is the source of the most rule-like behaviour in the profession. Notice also how narrow its examples are on their face. The five percent figure is paired with a manufacturer, and the revenue percentage is paired with a not-for-profit. Practice generalised both beyond their stated scope.

The paragraph that licenses the arithmetic itself is A4, and it is guidance too.

CAS 320, paragraph A4, first two sentences Application material Periods ending on or after 14 Dec 2010

Determining materiality involves the exercise of professional judgment. A percentage is often applied to a chosen benchmark as a starting point in determining materiality for the financial statements as a whole.

Note the register: "is often applied", not "shall be applied". A4 describes practice. It does not authorise it. The rest of A4, listing the factors that may affect the choice of benchmark, is in section 2.

0.3 Why the corrected version is the better thesis

The profession's most-quoted number is not folklore that grew up outside the standard. It sits inside the standard, one shelf below the "shall" paragraphs, in material the auditor is required to consider but not required to follow. Practice took an illustration offered as one example among many and hardened it into a default.

That makes the distinction between a requirement and application material, which the brief's constraints correctly call the fatal error to make, the argument itself rather than a citation rule.

0.4 The 0.5 percent of revenue rule, which has no textual home at all

0.5 Clearly trivial, the same pattern a third time

The "clearly trivial" threshold, which practice sets at roughly 5 percent of overall materiality, has no percentage anywhere in the Handbook either. CAS 450 requires the auditor to document the amount, at paragraph 16(a), and never says what the amount should be. The practice figures are in section 3 and CAS 450 itself is in section 4.

0.6 Proof that these are not artefacts of where I looked

Both negative results were tested by full-text search across the entire CPA Canada Standards and Guidance Collection, not just CAS 320.

The four non-Assurance hits on "five percent" sit in accounting and public sector material and none of them concerns audit materiality; they are named in section 3. Retrieved 21 August 2026.

All Handbook text was retrieved on 21 August 2026 from the CPA Canada Standards and Guidance Collection on Knotia, through the University of Waterloo library proxy. The edition is the CPA Canada Handbook – Assurance, revised to Update No. 51 (07/26), collection dated July 2026, with the Preface effective as of 1 July 2026.

Because the CAS text was retrieved directly, the paywall caveat in the brief does not apply to CAS 320, CAS 450, CAS 530, CAS 315, CAS 600 or the Preface. Every quoted Handbook paragraph below is verbatim from the July 2026 collection. Knotia document IDs are given where I captured them, so the exact document can be refetched.

Full text could not be retrieved for several academic articles behind publisher paywalls. Those are flagged individually where they appear.

CAS 320, Materiality in Planning and Performing an Audit. Knotia document ID B6w43TbRQTpOdzvcRzUU9zg. The header reads "(Effective for audits of financial statements for periods ending on or after December 14, 2010)". Paragraph 7, which is introduction and not a requirement, repeats it: "This CAS is effective for audits of financial statements for periods ending on or after December 14, 2010."

2.1 The definition of materiality the standard adopts

CAS 320 does not define materiality. It borrows the financial reporting framework's concept and describes it. Paragraph 2 is introductory, not a requirement.

CAS 320, paragraph 2 Introductory Periods ending on or after 14 Dec 2010

Financial reporting frameworks often discuss the concept of materiality in the context of the preparation and presentation of financial statements. Although financial reporting frameworks may discuss materiality in different terms, they generally explain that:

• Misstatements, including omissions, are considered to be material if they, individually or in the aggregate, could reasonably be expected to influence the economic decisions of users taken on the basis of the financial statements;
• Judgments about materiality are made in light of surrounding circumstances, and are affected by the size or nature of a misstatement, or a combination of both; and
• Judgments about matters that are material to users of the financial statements are based on a consideration of the common financial information needs of users as a group. The possible effect of misstatements on specific individual users, whose needs may vary widely, is not considered.

CAS 320, paragraph 3 Introductory Periods ending on or after 14 Dec 2010

the characteristics referred to in paragraph 2 provide the auditor with such a frame of reference.

Quoted in part. Paragraph 3 deals with the case where the financial reporting framework does not discuss materiality. Only the phrase above was captured.

CAS 320, paragraph 4 Introductory Periods ending on or after 14 Dec 2010

Understand that financial statements are prepared, presented and audited to levels of materiality.

Quoted in part. Paragraph 4 sets out four assumptions about users, at (a) to (d). Only the assumption above was captured.

Paragraph 6 carries the sentence that most undercuts a mechanical reading of any number the auditor sets.

CAS 320, paragraph 6 Introductory Periods ending on or after 14 Dec 2010

The materiality determined when planning the audit does not necessarily establish an amount below which uncorrected misstatements, individually or in the aggregate, will always be evaluated as immaterial. The circumstances related to some misstatements may cause the auditor to evaluate them as material even if they are below materiality.

2.2 Definitions, paragraph 9

Two defined terms, and the second one is recent. The paragraph opens: "9. For purposes of the CASs, the following terms have the meanings attributed below:"

CAS 320, paragraph 9(a) Definition Periods beginning on or after 15 Dec 2023

(a) Performance materiality – The amount or amounts set by the auditor at less than materiality for the financial statements as a whole to reduce aggregation risk to an appropriately low level. If applicable, performance materiality also refers to the amount or amounts set by the auditor at less than the materiality level or levels for particular classes of transactions, account balances or disclosures.

Amended by CAS 600. CPA Canada Handbook – Assurance Highlight Summary No. 38, August 2022, records that issuing revised CAS 600 amended "CAS 320, Materiality in Planning and Performing an Audit, paragraph 9."

CAS 320, paragraph 9(b) Definition Periods beginning on or after 15 Dec 2023

(b) Aggregation risk – The probability that the aggregate of uncorrected and undetected misstatements exceeds materiality for the financial statement as a whole.

New term. Aggregation risk arrives with the same CAS 600 amendment recorded in Highlight Summary No. 38.

The document carries the note "[Former paragraph 320.9 retained in Archived Pronouncements.]" On the effective date, the same Highlight Summary states: "Revised CAS 600 is effective for audits of financial statements for periods beginning on or after December 15, 2023. Earlier application is permitted." So the current definition of performance materiality has been in force for periods beginning on or after 15 December 2023.

2.3 The requirements, verbatim

CAS 320, paragraph 10 Requirement Periods ending on or after 14 Dec 2010

When establishing the overall audit strategy, the auditor shall determine materiality for the financial statements as a whole. If, in the specific circumstances of the entity, there is one or more particular classes of transactions, account balances or disclosures for which misstatements of lesser amounts than materiality for the financial statements as a whole could reasonably be expected to influence the economic decisions of users taken on the basis of the financial statements, the auditor shall also determine the materiality level or levels to be applied to those particular classes of transactions, account balances or disclosures. (Ref: Para. A3-A12)

CAS 320, paragraph 11 Requirement Periods ending on or after 14 Dec 2010

The auditor shall determine performance materiality for purposes of assessing the risks of material misstatement and determining the nature, timing and extent of further audit procedures. (Ref: Para. A13)

Eighteen words of obligation. No percentage, and no relationship to overall materiality other than the "less than" built into the definition at 9(a).

CAS 320, paragraph 12 Requirement Periods ending on or after 14 Dec 2010

The auditor shall revise materiality for the financial statements as a whole (and, if applicable, the materiality level or levels for particular classes of transactions, account balances or disclosures) in the event of becoming aware of information during the audit that would have caused the auditor to have determined a different amount (or amounts) initially. (Ref: Para. A14)

CAS 320, paragraph 13 Requirement Periods ending on or after 14 Dec 2010

If the auditor concludes that a lower materiality for the financial statements as a whole (and, if applicable, materiality level or levels for particular classes of transactions, account balances or disclosures) than that initially determined is appropriate, the auditor shall determine whether it is necessary to revise performance materiality, and whether the nature, timing and extent of the further audit procedures remain appropriate.

CAS 320, paragraph 14 Requirement Periods ending on or after 14 Dec 2010

The auditor shall include in the audit documentation the following amounts and the factors considered in their determination:

(a) Materiality for the financial statements as a whole (see paragraph 10);

(b) If applicable, the materiality level or levels for particular classes of transactions, account balances or disclosures (see paragraph 10);

(c) Performance materiality (see paragraph 11); and

(d) Any revision of (a)-(c) as the audit progressed (see paragraphs 12-13).

2.4 The load-bearing answer: where the percentages appear

The percentages appear in application material only, at A4, A5 and A8. Nowhere in the requirements.

CAS 320, paragraph A4 Application material Periods ending on or after 14 Dec 2010

Determining materiality involves the exercise of professional judgment. A percentage is often applied to a chosen benchmark as a starting point in determining materiality for the financial statements as a whole. Factors that may affect the identification of an appropriate benchmark include the following:

• The elements of the financial statements (for example, assets, liabilities, equity, revenue, expenses);
• Whether there are items on which the attention of the users of the particular entity's financial statements tends to be focused (for example, for the purpose of evaluating financial performance users may tend to focus on profit, revenue or net assets);
• The nature of the entity, where the entity is in its life cycle, and the industry and economic environment in which the entity operates;
• The entity's ownership structure and the way it is financed (for example, if an entity is financed solely by debt rather than equity, users may put more emphasis on assets, and claims on them, than on the entity's earnings); and
• The relative volatility of the benchmark.

Note the register. "is often applied", not "shall be applied". A4 reports what practice does. It does not require it.

CAS 320, paragraph A5 Application material Periods ending on or after 14 Dec 2010

Examples of benchmarks that may be appropriate, depending on the circumstances of the entity, include categories of reported income such as profit before tax, total revenue, gross profit and total expenses, total equity or net asset value. Profit before tax from continuing operations is often used for profit-oriented entities. When profit before tax from continuing operations is volatile, other benchmarks may be more appropriate, such as gross profit or total revenues.

Paragraph A8, the one the argument turns on

CAS 320, paragraph A8 Application material Periods ending on or after 14 Dec 2010

Determining a percentage to be applied to a chosen benchmark involves the exercise of professional judgment. There is a relationship between the percentage and the chosen benchmark, such that a percentage applied to profit before tax from continuing operations will normally be higher than a percentage applied to total revenue. For example, the auditor may consider five percent of profit before tax from continuing operations to be appropriate for a profit-oriented entity in a manufacturing industry, while the auditor may consider one percent of total revenue or total expenses to be appropriate for a not-for-profit entity. Higher or lower percentages, however, may be deemed appropriate in the circumstances.

The rest of the benchmark guidance

CAS 320, paragraph A6 Application material Periods ending on or after 14 Dec 2010

a normalized profit before tax from continuing operations figure based on past results.

Quoted in part. A6 adds the normalisation point: where an exceptional swing in profit before tax occurs, the auditor may use the figure quoted above.

CAS 320, paragraph A9 Application material Periods ending on or after 14 Dec 2010

When an entity's profit before tax from continuing operations is consistently nominal, as might be the case for an owner-managed business where the owner takes much of the profit before tax in the form of remuneration, a benchmark such as profit before remuneration and tax may be more relevant.

Small entities. A9 is the small-entity guidance, and what it moves is the benchmark. No percentage is mentioned.

CAS 320, paragraph A10 Paraphrase Application material Periods ending on or after 14 Dec 2010

Total cost or net cost may be appropriate for program activities; assets may be appropriate where the entity has custody of public assets.

Public sector, summarised not quoted. The research pack records the substance of A10 but did not capture its verbatim text. Refetch before quoting.

CAS 320, paragraph A3 Application material Periods ending on or after 14 Dec 2010

Materiality "is therefore influenced by law, regulation or other authority, and by the financial information needs of legislators and the public in relation to public sector programs."

Public sector, quoted in part. Only the phrase in quotation marks is verbatim.

2.5 Materiality for particular classes, balances or disclosures

The requirement is the second sentence of paragraph 10, quoted above. The guidance under it is A11 and A12.

CAS 320, paragraph A11 Paraphrase Application material Periods ending on or after 14 Dec 2010

Indicators that a lower materiality may be needed for particular classes, balances or disclosures:

• law, regulation or framework affecting user expectations (related party transactions, management remuneration, sensitivity analysis for high-uncertainty fair value estimates);
• key industry disclosures (research and development for a pharmaceutical company);
• separately disclosed aspects (segments, a significant business combination).

Summarised, not quoted. The research pack lists A11's indicators without capturing its verbatim text. Refetch before quoting.

CAS 320, paragraph A12 Application material Periods ending on or after 14 Dec 2010

The auditor "may find it useful to obtain an understanding of the views and expectations of those charged with governance and management."

Quoted in part. Only the phrase in quotation marks is verbatim.

No percentage in either. Nothing resembling a rule.

2.6 Performance materiality guidance

A13 is the only application paragraph on performance materiality. It is quoted here in the relevant part, with the ellipsis as the research pack gives it.

CAS 320, paragraph A13 Application material Periods beginning on or after 15 Dec 2023

Planning the audit solely to detect individually material misstatements overlooks the fact that the aggregate of individually immaterial misstatements may cause the financial statements to be materially misstated, and leaves no margin for possible undetected misstatements. Performance materiality (which, as defined, is one or more amounts) is set at less than materiality for the financial statements as a whole to reduce aggregation risk to an appropriately low level. ... The determination of performance materiality is not a simple mechanical calculation and involves the exercise of professional judgment. It is affected by the auditor's understanding of the entity, updated during the performance of the risk assessment procedures; and the nature and extent of misstatements identified in previous audits and thereby the auditor's expectations in relation to misstatements in the current period.

Amended text. The document carries "[Former paragraph 320.A13 retained in Archived Pronouncements.]", consistent with the CAS 600 conforming amendment, so this wording carries the amendment's date shown above, periods beginning on or after 15 Dec 2023, not the standard's 2010 header date.

3.1 What is authoritative in Canada

One paragraph. CAS 320 paragraph A8, application material, quoted in full in section 02. It supports "five percent of profit before tax from continuing operations" as an example for a profit-oriented manufacturer, and "one percent of total revenue or total expenses" as an example for a not-for-profit.

Handbook-wide negative searches

Run 21 August 2026 on the July 2026 collection.

• "five percent": five documents across the whole collection. Exactly one is in Assurance, and it is CAS 320. The others are ASPE 3063, ASPE 3870, PS 3450 and an archived PS 3450 supplement, all unrelated to audit materiality.
• "one percent of total revenue": one document in the whole collection, CAS 320.
• "sample size" AND "monetary unit": one document, CAS 530, and the hit is Appendix 4(c), which describes monetary unit sampling without a formula.

3.2 What is not authoritative, and is where the numbers really live

I looked for CPA Canada guidance setting benchmarks. I did not find any. Neither an Assurance and Related Services Guideline, nor a Canadian Auditing Practice Note, nor a CPA Canada publication giving materiality percentages, surfaced in the Handbook search or in web search.

What does exist is documented firm methodology, captured by regulators and academics. All three of the sources below are non-Canadian, and the piece must label them.

(a) CEAOB, European Union: the Big 4 benchmark grid

CEAOB, Report on the CEAOB Survey: Materiality in the Context of an Audit, July 2022. A European Union and EEA regulator, not Canadian. Scope: 495 public interest entity audit files across 21 EEA countries; the methodologies of the four largest firms; 247 audit committee chairs across 15 EEA countries.

Observed average percentages actually applied to profit before tax in the sampled files: 5.52, 4.92, 6.91 and 4.81 percent for Firms A to D.

Performance materiality, expected percentages of overall materiality: Firm A "50% or 75%"; Firm B "50%, 75% or 90%"; Firm C no predetermined grid; Firm D "50%, 65% or 75%". Observed averages on recurrent engagements ranged from 63.31 to 76.59 percent across firms.

On the clearly trivial threshold, the stated ranges are: Firm A "5% (by default) or lower"; Firm B "0%, 3%, 5% or 10%"; Firm C "Up to 5%"; Firm D "3% to 5%". The report puts the common ground plainly.

CEAOB, Report on the CEAOB Survey: Materiality in the Context of an Audit European Union / EEA Regulator report July 2022

"A consensus around 5% of OM seems to be broadly shared among the Big 4 firms."

OM: overall materiality. The consensus is a consensus among firms, recorded by a regulator, not a requirement of any standard.

(b) FRC, United Kingdom: eight firms, thirty-two audits

FRC, Audit Quality Thematic Review: Materiality, December 2017. A United Kingdom regulator, not Canadian. Scope: 8 audit firms, 32 audits reviewed.

FRC, Audit Quality Thematic Review: Materiality United Kingdom Regulator report December 2017

"It is therefore possible that the materiality levels set by firms A, E, G and H could be around 100% higher than that of the more prudent firms, B, D, and F."

Read it correctly: a regulator saying in print that the same set of financial statements could attract a materiality figure twice as large depending on which firm signs, under a standard that contains a single illustrative percentage.

(c) Eilifsen and Messier (2015), United States firms

Citation: Eilifsen, A., and W. F. Messier Jr. 2015. "Materiality Guidance of the Major Public Accounting Firms." AUDITING: A Journal of Practice & Theory 34 (2): 3-26. Academic, covering United States firms, not Canadian. Scope: the internal materiality guidance of eight of the largest U.S. public accounting firms.

Eilifsen and Messier, Materiality Guidance of the Major Public Accounting Firms United States Academic 2015

"Seven firms use a percentage of overall materiality for determining tolerable misstatement that fits in a 50 to 75 percent range; one firm uses a range of 70 to 90 percent."

"Seven of the firms establish a clearly trivial misstatement to be 3 to 5 percent of overall materiality; one firm uses a range of 5 to 8 percent."

3.3 United States authority on the 5 percent rule, for contrast

SEC Staff Accounting Bulletin No. 99, Materiality, released 12 August 1999. Not Canadian, no application in Canada, and directly useful as contrast because it is the most explicit official statement anywhere on the status of the 5 percent rule.

SEC Staff Accounting Bulletin No. 99, Materiality United States SEC staff guidance Released 12 August 1999

"The use of a percentage as a numerical threshold, such as 5%, may provide the basis for a preliminary assumption that – without considering all relevant circumstances – a deviation of less than the specified percentage with respect to a particular item on the registrant's financial statements is unlikely to be material."

"The staff has no objection to such a 'rule of thumb' as an initial step in assessing materiality."

"The staff reminds registrants and the auditors of their financial statements that exclusive reliance on this or any percentage or numerical threshold has no basis in the accounting literature or the law."

The United States audit standard on the same subject is more austere still.

PCAOB AS 2105, Consideration of Materiality in Planning and Performing an Audit, paragraphs .06 and .08 United States PCAOB standard Audits of fiscal years beginning on or after 15 Dec 2010

.06 To plan the nature, timing, and extent of audit procedures, the auditor should establish a materiality level for the financial statements as a whole that is appropriate in light of the particular circumstances. This includes consideration of the company's earnings and other relevant factors.

.08 The auditor should determine the amount or amounts of tolerable misstatement for purposes of assessing risks of material misstatement and planning and performing audit procedures at the account or disclosure level. The auditor should determine tolerable misstatement at an amount or amounts that reduce to an appropriately low level the probability that the total of uncorrected and undetected misstatements would result in material misstatement of the financial statements.

3.4 Honest bottom line

CAS 450, Evaluation of Misstatements Identified during the Audit. Knotia document ID BSJH7_QEkRTiKjzBYarnZDg. The header reads "(Effective for audits of financial statements for periods ending on or after December 14, 2010)", carrying an asterisked note: "The effective date of paragraph 8 differs from that in corresponding ISA 450. The Preface to the CPA Canada Handbook – Assurance provides an explanation." Requirements are paragraphs 5 to 16. Application material is A1 to A31.

4.0 Three effective dates in one standard

The standard does not have a single date. It has three, and each attaches to different paragraphs. All three of the paragraphs that say so are introductory, not requirements.

CAS 450, paragraph 2 Introductory Periods ending on or after 14 Dec 2010

This CAS is effective for audits of financial statements for periods ending on or after December 14, 2010.

CAS 450, paragraph C2A Introductory Paragraph 8: periods ending on or after 15 Dec 2018

The issuance of CAS 250, Consideration of Laws and Regulations in an Audit of Financial Statements, gave rise to a conforming amendment in paragraph 8. Paragraph 8 is effective for periods ending on or after December 15, 2018.

The C prefix marks a Canadian amendment. A paragraph numbered C2A is text the Canadian standard carries that the corresponding ISA does not, which is why the header's asterisked note says the effective date of paragraph 8 differs from that in ISA 450 and points to the Preface for the explanation.

CAS 450, paragraph 2B Introductory Paragraph 6: periods beginning on or after 15 Dec 2026

The issuance of CAS 240, The Auditor's Responsibilities Relating to Fraud in an Audit of Financial Statements, gave rise to conforming amendments in paragraph 6. Paragraph 6 is effective for audits of financial statements for periods beginning on or after December 15, 2026.

4.1 Accumulation and the clearly trivial threshold

Two requirement paragraphs carry the threshold. One says accumulate above it, the other says document it.

CAS 450, paragraph 5 Requirement Periods ending on or after 14 Dec 2010

The auditor shall accumulate misstatements identified during the audit, other than those that are clearly trivial. (Ref: Para. A2-A6)

CAS 450, paragraph 16(a) Requirement Periods ending on or after 14 Dec 2010

The auditor shall document "The amount below which misstatements would be regarded as clearly trivial (paragraph 5)".

Quoted in part. Only the phrase inside the quotation marks is verbatim from the standard; the lead-in is the research pack's.

The application material explains what clearly trivial is not.

CAS 450, paragraph A2 Application material Periods ending on or after 14 Dec 2010

Paragraph 5 requires the auditor to accumulate misstatements identified during the audit other than those that are clearly trivial. 'Clearly trivial' is not another expression for 'not material.' Misstatements that are clearly trivial will be of a wholly different (smaller) order of magnitude or of a wholly different nature than those that would be determined to be material, and will be misstatements that are clearly inconsequential, whether taken individually or in aggregate and whether judged by any criteria of size, nature or circumstances. When there is any uncertainty about whether one or more items are clearly trivial, the misstatement is considered not to be clearly trivial.

Definition by negation, plus a tie breaker. "A wholly different order of magnitude" is an order-of-magnitude instruction, which is not the same thing as 5 percent, and practice reads it as 5 percent. The last sentence resolves uncertainty against triviality.

CAS 450, paragraph A3 Application material Periods ending on or after 14 Dec 2010

The auditor may designate an amount below which misstatements of amounts in the individual statements would be clearly trivial, and would not need to be accumulated because the auditor expects that the accumulation of such amounts clearly would not have a material effect on the financial statements. However, misstatements of amounts that are above the designated amount are accumulated as required by paragraph 5. In addition, misstatements relating to amounts may not be clearly trivial when judged on criteria of nature or circumstances, and, if not, are accumulated as required by paragraph 5.

"May designate" in guidance, "shall document the amount" in requirement 16(a). Worth flagging the small awkwardness: the requirement to document presupposes the optional act.

CAS 450, paragraph A4 Paraphrase Application material Periods ending on or after 14 Dec 2010

A4 extends clearly trivial to disclosures.

Not quoted. The research pack records only what A4 does, not its wording. Refetch before quoting.

CAS 450, paragraph A6 Application material Periods ending on or after 14 Dec 2010

Factual misstatements are misstatements about which there is no doubt.

Judgmental misstatements are differences arising from the judgments of management including those concerning recognition, measurement, presentation and disclosure in the financial statements (including the selection or application of accounting policies) that the auditor considers unreasonable or inappropriate.

Projected misstatements are the auditor's best estimate of misstatements in populations, involving the projection of misstatements identified in audit samples to the entire populations from which the samples were drawn.

Even the taxonomy is guidance. A6 says "it may be useful to distinguish". The three-way split that practice runs on carries no obligation.

The one requirement anywhere that caps a clearly trivial threshold

CAS 600 (Revised), paragraph 35(b) Requirement Periods beginning on or after 15 Dec 2023

(b) The threshold above which misstatements identified in the component financial information are to be communicated to the group auditor. Such threshold shall not exceed the amount regarded as clearly trivial to the group financial statements. (Ref: Para. A121)

4.2 The relationship between the clearly trivial threshold and materiality

There is no stated numerical relationship between the two. What the standard gives instead is a trigger and an explanation of it.

CAS 450, paragraph 7(b) Requirement Periods ending on or after 14 Dec 2010

The auditor shall determine whether the strategy and plan need revision if "The aggregate of misstatements accumulated during the audit approaches materiality determined in accordance with CAS 320. (Ref: Para. A8)"

Quoted in part. Only the text inside the quotation marks is verbatim; the lead-in is the research pack's.

CAS 450, paragraph A9 Application material Periods ending on or after 14 Dec 2010

If the aggregate of misstatements accumulated during the audit approaches materiality determined in accordance with CAS 320, there may be a greater than acceptably low level of risk that possible undetected misstatements, when taken with the aggregate of misstatements accumulated during the audit, could exceed materiality. Undetected misstatements could exist because of the presence of sampling risk and non-sampling risk.

That is the conceptual link. Clearly trivial sits below the accumulation line, accumulation feeds the aggregate, the aggregate is measured against materiality, and the buffer for what was never found is performance materiality. The chain is fully specified in concept and entirely unspecified in quantity.

4.3 Reassessing materiality before evaluating

CAS 450, paragraph 11 Requirement Periods ending on or after 14 Dec 2010

Prior to evaluating the effect of uncorrected misstatements, the auditor shall reassess materiality determined in accordance with CAS 320 to confirm whether it remains appropriate in the context of the entity's actual financial results. (Ref: Para. A15-A16)

CAS 450, paragraph A15 Application material Periods ending on or after 14 Dec 2010

The auditor's determination of materiality in accordance with CAS 320 is often based on estimates of the entity's financial results, because the actual financial results may not yet be known. Therefore, prior to the auditor's evaluation of the effect of uncorrected misstatements, it may be necessary to revise materiality determined in accordance with CAS 320 based on the actual financial results.

4.4 Uncorrected misstatements

Six requirement paragraphs run from communication through evaluation to written representation.

CAS 450, paragraph 9 Paraphrase Requirement Periods ending on or after 14 Dec 2010

Communicate all accumulated misstatements to the appropriate level of management on a timely basis and request correction.

Not quoted. The research pack records the substance of paragraph 9, not its wording. Refetch before quoting.

CAS 450, paragraph 10 Paraphrase Requirement Periods ending on or after 14 Dec 2010

If management refuses, obtain an understanding of its reasons and take that understanding into account.

Not quoted. The research pack records the substance of paragraph 10, not its wording. Refetch before quoting.

CAS 450, paragraph 12 Requirement Periods ending on or after 14 Dec 2010

The auditor shall determine whether uncorrected misstatements are material, individually or in aggregate. In making this determination, the auditor shall consider:

• (a) The size and nature of the misstatements, both in relation to particular classes of transactions, account balances or disclosures and the financial statements as a whole, and the particular circumstances of their occurrence; and (Ref: Para. A17-A23, A25-A26)
• (b) The effect of uncorrected misstatements related to prior periods on the relevant classes of transactions, account balances or disclosures, and the financial statements as a whole. (Ref: Para. A24)

CAS 450, paragraph 13 Requirement Periods ending on or after 14 Dec 2010

Communicate uncorrected misstatements to those charged with governance. "The auditor's communication shall identify material uncorrected misstatements individually. The auditor shall request that uncorrected misstatements be corrected."

Quoted in part. Only the text inside the quotation marks is verbatim; the lead-in is the research pack's.

CAS 450, paragraph 14 Requirement Periods ending on or after 14 Dec 2010

The auditor shall also communicate with those charged with governance the effect of uncorrected misstatements related to prior periods on the relevant classes of transactions, account balances or disclosures, and the financial statements as a whole.

CAS 450, paragraph 15 Paraphrase Requirement Periods ending on or after 14 Dec 2010

Written representation from management, and where appropriate those charged with governance, on whether they believe the effects of uncorrected misstatements are immaterial, with a summary attached.

Not quoted. The research pack records the substance of paragraph 15, not its wording. Refetch before quoting.

The application material supporting paragraph 12 is where the judgment actually sits.

CAS 450, paragraph A20 Application material Periods ending on or after 14 Dec 2010

If an individual misstatement is judged to be material, it is unlikely that it can be offset by other misstatements. For example, if revenue has been materially overstated, the financial statements as a whole will be materially misstated, even if the effect of the misstatement on earnings is completely offset by an equivalent overstatement of expenses. It may be appropriate to offset misstatements within the same account balance or class of transactions; however, the risk that further undetected misstatements may exist is considered before concluding that offsetting even immaterial misstatements is appropriate.

Offsetting. The rule that a material misstatement cannot be netted away is application material, not a requirement.

CAS 450, paragraph A21 Application material Periods ending on or after 14 Dec 2010

A classification misstatement may be immaterial to the statements as a whole "even though it may exceed the materiality level or levels applied in evaluating other misstatements."

Quoted in part. Only the phrase inside the quotation marks is verbatim; the lead-in is the research pack's.

CAS 450, paragraph A22 Paraphrase Application material Periods ending on or after 14 Dec 2010

The qualitative circumstances in which an otherwise small misstatement may be material:

• regulatory compliance;
• debt covenants;
• a policy error immaterial now and material later;
• masking a change in earnings or other trends;
• ratios;
• segment information;
• management compensation;
• previous communications to users such as forecast earnings;
• related parties;
• an omission not required by the framework but important to users;
• effects on other information under CAS 720.

It closes: "These circumstances are only examples; not all are likely to be present in all audits nor is the list necessarily complete."

Listed, not quoted. The bullets are the research pack's summary of A22's circumstances. Only the closing sentence is verbatim.

CAS 450, paragraph A28 Application material Periods ending on or after 14 Dec 2010

Where there are many individually immaterial uncorrected misstatements, the auditor may communicate "the number and overall monetary effect" rather than each item.

Quoted in part. Only the phrase inside the quotation marks is verbatim; the lead-in is the research pack's.

4.5 Iron curtain versus rollover: the answer is that CAS 450 does not choose

CAS 450, paragraph A24 Application material Periods ending on or after 14 Dec 2010

The cumulative effect of immaterial uncorrected misstatements related to prior periods may have a material effect on the current period's financial statements. There are different acceptable approaches to the auditor's evaluation of such uncorrected misstatements on the current period's financial statements. Using the same evaluation approach provides consistency from period to period.

Three sentences. It acknowledges the problem, permits more than one answer, and requires only that you not switch answers between years. That is the entire Canadian authority on iron curtain versus rollover.

The vocabulary comes from a United States source, and should be labelled as one. SEC Staff Accounting Bulletin No. 108, "Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements", was released and effective 13 September 2006.

SEC Staff Accounting Bulletin No. 108, the two definitions United States SEC staff guidance 13 September 2006

Rollover: it "quantifies a misstatement based on the amount of the error originating in the current year income statement."

Iron curtain: it "quantifies a misstatement based on the effects of correcting the misstatement existing in the balance sheet at the end of the current year, irrespective of the misstatement's year(s) of origination."

Quoted in part. Only the text inside the quotation marks is verbatim; the labels are the research pack's.

SEC Staff Accounting Bulletin No. 108, the staff position United States SEC staff guidance 13 September 2006

"The staff does not believe the exclusive reliance on either the rollover or iron curtain approach appropriately quantifies all misstatements that could be material to users of financial statements", and "a registrant's financial statements would require adjustment when either approach results in quantifying a misstatement that is material, after considering all relevant quantitative and qualitative factors."

CAS 530, Audit Sampling. Knotia document ID BbYFYi73BQCihRanlNoxMDQ. Header and paragraph 3: "(Effective for audits of financial statements for periods ending on or after December 14, 2010)". No amending paragraphs. No C-prefixed paragraphs. Nothing in the Preface Appendix 2 table. Every paragraph in this section therefore carries one date, and there are no Canadian amendments to separate out.

Requirements are paragraphs 6 to 15. Application material is A1 to A23, plus four appendices which are part of the standard but are application material by reference: Appendix 1 is referenced from A8, Appendices 2 and 3 from A11, Appendix 4 from A13.

5.1 Statistical versus non-statistical

CAS 530, paragraph 5(g) Definition Periods ending on or after 14 Dec 2010

Statistical sampling – An approach to sampling that has the following characteristics:

• (i) Random selection of the sample items; and
• (ii) The use of probability theory to evaluate sample results, including measurement of sampling risk.

A sampling approach that does not have characteristics (i) and (ii) is considered non-statistical sampling.

Residual only. Non-statistical sampling is defined only as the residual. There is no positive definition.

CAS 530, paragraph A9 Application material Periods ending on or after 14 Dec 2010

The decision whether to use a statistical or non-statistical sampling approach is a matter for the auditor's judgment; however, sample size is not a valid criterion to distinguish between statistical and non-statistical approaches.

CAS 530, paragraph A11 Application material Periods ending on or after 14 Dec 2010

The sample size can be determined by the application of a statistically-based formula or through the exercise of professional judgment. Appendices 2 and 3 indicate the influences that various factors typically have on the determination of sample size. When circumstances are similar, the effect on sample size of factors such as those identified in Appendices 2 and 3 will be similar regardless of whether a statistical or non-statistical approach is chosen.

Where the appendices come from. This is the paragraph that pulls Appendices 2 and 3 into the standard, and it is guidance.

CAS 530, paragraph A12 Application material Periods ending on or after 14 Dec 2010

With statistical sampling, sample items are selected in a way that each sampling unit has a known probability of being selected. With non-statistical sampling, judgment is used to select sample items.

CAS 530, paragraph 8 Requirement Periods ending on or after 14 Dec 2010

The auditor shall select items for the sample in such a way that each sampling unit in the population has a chance of selection.

The only constraint on selection. Paragraph 8 is the whole of the obligation about how items are picked.

5.2 Sampling risk versus non-sampling risk

CAS 530, paragraph 5(c) Definition Periods ending on or after 14 Dec 2010

Sampling risk – The risk that the auditor's conclusion based on a sample may be different from the conclusion if the entire population were subjected to the same audit procedure. Sampling risk can lead to two types of erroneous conclusions:

• (i) In the case of a test of controls, that controls are more effective than they actually are, or in the case of a test of details, that a material misstatement does not exist when in fact it does. The auditor is primarily concerned with this type of erroneous conclusion because it affects audit effectiveness and is more likely to lead to an inappropriate audit opinion.
• (ii) In the case of a test of controls, that controls are less effective than they actually are, or in the case of a test of details, that a material misstatement exists when in fact it does not. This type of erroneous conclusion affects audit efficiency as it would usually lead to additional work to establish that initial conclusions were incorrect.

CAS 530, paragraph 5(d) Definition Periods ending on or after 14 Dec 2010

Non-sampling risk – The risk that the auditor reaches an erroneous conclusion for any reason not related to sampling risk. (Ref: Para. A1)

CAS 530, paragraph A1 Application material Periods ending on or after 14 Dec 2010

Examples of non-sampling risk include use of inappropriate audit procedures, or misinterpretation of audit evidence and failure to recognize a misstatement or deviation.

CAS 530, paragraph 5(e) Definition Periods ending on or after 14 Dec 2010

Anomaly – A misstatement or deviation that is demonstrably not representative of misstatements or deviations in a population.

CAS 530, paragraph 13 Requirement Periods ending on or after 14 Dec 2010

In the extremely rare circumstances when the auditor considers a misstatement or deviation discovered in a sample to be an anomaly, the auditor shall obtain a high degree of certainty that such misstatement or deviation is not representative of the population. The auditor shall obtain this degree of certainty by performing additional audit procedures to obtain sufficient appropriate audit evidence that the misstatement or deviation does not affect the remainder of the population.

Unusually strict. This requirement governs anomalies, and unlike most of CAS 530 it sets the bar in the text of the obligation itself: extremely rare circumstances, a high degree of certainty, additional procedures.

5.3 Tolerable misstatement and performance materiality

This is a clean, quotable answer, and the relationship is stated in application material, not in a requirement.

CAS 530, paragraph 5(i) Definition Periods ending on or after 14 Dec 2010

Tolerable misstatement – A monetary amount set by the auditor in respect of which the auditor seeks to obtain an appropriate level of assurance that the monetary amount set by the auditor is not exceeded by the actual misstatement in the population. (Ref: Para. A3)

CAS 530, paragraph A3 Application material Periods ending on or after 14 Dec 2010

When designing a sample, the auditor determines tolerable misstatement in order to address the risk that the aggregate of individually immaterial misstatements may cause the financial statements to be materially misstated and provide a margin for possible undetected misstatements. Tolerable misstatement is the application of performance materiality, as defined in CAS 320, to a particular sampling procedure. Tolerable misstatement may be the same amount or an amount lower than performance materiality.

Load-bearing. The link between the sampling standard and the materiality standard is made here, in guidance, and nowhere in the requirements.

CAS 530, paragraph 5(j) Definition Periods ending on or after 14 Dec 2010

Tolerable rate of deviation – A rate of deviation from prescribed internal control procedures set by the auditor in respect of which the auditor seeks to obtain an appropriate level of assurance that the rate of deviation set by the auditor is not exceeded by the actual rate of deviation in the population.

5.4 Projection of misstatements

CAS 530, paragraph 14 Requirement Periods ending on or after 14 Dec 2010

For tests of details, the auditor shall project misstatements found in the sample to the population. (Ref: Para. A18-A20)

Eighteen words. The standard requires projection and does not say how to project.

CAS 530, paragraph A18 Application material Periods ending on or after 14 Dec 2010

The auditor is required to project misstatements for the population to obtain a broad view of the scale of misstatement but this projection may not be sufficient to determine an amount to be recorded.

CAS 530, paragraph A19 Application material Periods ending on or after 14 Dec 2010

When a misstatement has been established as an anomaly, it may be excluded when projecting misstatements to the population. However, the effect of any such misstatement, if uncorrected, still needs to be considered in addition to the projection of the non-anomalous misstatements.

CAS 530, paragraph A20 Application material Periods ending on or after 14 Dec 2010

For tests of controls, no explicit projection of deviations is necessary since the sample deviation rate is also the projected deviation rate for the population as a whole.

Appendix 1, paragraphs 3 and 4, govern projection under stratification: results within a stratum project only to that stratum, and the projected misstatements for each stratum are then combined when the effect on the total class of transactions or account balance is considered.

5.5 Evaluating results

CAS 530, paragraph 15 Requirement Periods ending on or after 14 Dec 2010

The auditor shall evaluate:

• (a) The results of the sample; and (Ref: Para. A21-A22)
• (b) Whether the use of audit sampling has provided a reasonable basis for conclusions about the population that has been tested. (Ref: Para. A23)

CAS 530, paragraph A22 Application material Periods ending on or after 14 Dec 2010

In the case of tests of details, the projected misstatement plus anomalous misstatement, if any, is the auditor's best estimate of misstatement in the population. When the projected misstatement plus anomalous misstatement, if any, exceeds tolerable misstatement, the sample does not provide a reasonable basis for conclusions about the population that has been tested. The closer the projected misstatement plus anomalous misstatement is to tolerable misstatement, the more likely that actual misstatement in the population may exceed tolerable misstatement. Also if the projected misstatement is greater than the auditor's expectations of misstatement used to determine the sample size, the auditor may conclude that there is an unacceptable sampling risk that the actual misstatement in the population exceeds the tolerable misstatement. Considering the results of other audit procedures helps the auditor to assess the risk that actual misstatement in the population exceeds tolerable misstatement, and the risk may be reduced if additional audit evidence is obtained.

The decision rule is in guidance. The comparison of projected plus anomalous misstatement against tolerable misstatement, which is what actually decides whether the sample worked, is stated at A22 and not in paragraph 15.

A23, application material, gives the responses when sampling has not provided a reasonable basis: ask management to investigate, or tailor the nature, timing and extent of further procedures, including extending the sample, testing an alternative control, or modifying substantive procedures.

5.6 How sample size moves: what CAS 530 actually says

Two requirements govern design and size, and they are the shortest in the standard.

CAS 530, paragraph 6 Requirement Periods ending on or after 14 Dec 2010

When designing an audit sample, the auditor shall consider the purpose of the audit procedure and the characteristics of the population from which the sample will be drawn. (Ref: Para. A4-A9)

CAS 530, paragraph 7 Requirement Periods ending on or after 14 Dec 2010

The auditor shall determine a sample size sufficient to reduce sampling risk to an acceptably low level. (Ref: Para. A10-A11)

Seventeen words. This is the entire obligation on sample size. Everything quantitative sits in guidance, in the appendices, or outside the standard altogether (section 06).

CAS 530, paragraph A10 Application material Periods ending on or after 14 Dec 2010

The level of sampling risk that the auditor is willing to accept affects the sample size required. The lower the risk the auditor is willing to accept, the greater the sample size will need to be.

Appendices 2 and 3 are directional tables only. No formula, no magnitude, no coefficients. Both are part of the standard but are application material by reference, pulled in from A11, and both are reproduced below as printed.

Item 7 is the only place in either appendix where a mechanism is named rather than a direction, and the parenthetical is the reason the "Negligible effect" entry does not mean what a reader might assume.

CAS 530, Appendix 2, item 5 explanatory text Application material Periods ending on or after 14 Dec 2010

For large populations, the actual size of the population has little, if any, effect on sample size. For small populations, however, audit sampling may not be as efficient as alternative means of obtaining sufficient appropriate audit evidence.

Appendix 4, Sample Selection Methods, lists five: random selection; systematic selection with a sampling interval; monetary unit sampling, described as "a type of value-weighted selection (as described in Appendix 1) in which sample size, selection and evaluation results in a conclusion in monetary amounts"; haphazard selection, which is not appropriate when using statistical sampling; and block selection, which "cannot ordinarily be used in audit sampling".

6.1 The Poisson relationship for monetary unit sampling

Not jurisdictional Source: Derks, K., Statistical Audit Sampling with R, chapter 4 (Planning), open access at https://alexrajcoomar.github.io/sasr/, and the documentation for the jfa R package version 0.7.4 (CRAN, dated 8 May 2026). Package citation: Derks, K., de Swart, J., Wagenmakers, E.-J., Wille, J., and Wetzels, R. (2021). "JASP for audit: Bayesian tools for the auditing practice." Journal of Open Source Software 6 (68): 2733. This is a statistics text and a software package, not a standard, and not a Canadian source.

With zero expected misstatements, the minimum sample size under a Poisson likelihood is:

The first line is the formula applied directly: n = ⌈−ln(0.05)/0.03⌉ = 100. For the other two the source states that with non-zero expected misstatements "it becomes more difficult to solve the formula for n algebraically", and the sample size is found by iteration; the upper bound "can also be obtained via percentiles of the gamma(1 + k, n) distribution."

The actual relationships, stated properly

1. Sample size is inversely proportional to tolerable misstatement, with zero expected misstatements. Halve tolerable misstatement and the sample size exactly doubles. This is CAS 530 Appendix 3 item 4's "Decrease", made exact.
2. Sample size is logarithmic in the accepted risk. Because the numerator is −ln(α), each step up in confidence costs more than the last. Assurance is cheap at the bottom and expensive at the top. This is Appendix 3 item 3's "Increase", made exact. The numbers behind it are in the box above, and they are mine.
3. Expected misstatement is the expensive input. At α = 0.05 and θ_max = 0.03, moving from zero to one expected misstatement takes the sample from 100 to 159, and 1.5 expected misstatements takes it to 185. Those three figures are the source's. This is Appendix 3 item 5's "Increase", made exact, and it explains a behaviour the standard never mentions: an auditor who expects to find nothing buys a much smaller sample than one who expects to find something, which creates an incentive the standard does not address.
4. Population size does not appear in the formula at all. That is exactly why Appendix 3 item 7 says "Negligible effect", and it is a genuinely counterintuitive result worth explaining to a reader.

6.2 The practitioner form of the same thing, US-sourced

Confidence-factor form, factors attributed to AICPA Audit Sampling Guide, tables C-2 and C-4 United States Practitioner source Edition and date not retrieved

n = (Book value × Reliability factor) / (Tolerable misstatement − (Expected misstatement × Expansion factor))

Second-hand. The formula was taken from a practitioner site that attributes the reliability and expansion factors to the two AICPA tables named above.

6.3 Canadian origin of monetary unit sampling, partially verified

Monetary unit sampling, originally dollar-unit sampling, has a Canadian lineage worth a sentence in the piece. The standard reference is Leslie, D. A., Teitlebaum, A. D., and Anderson, R. J., Dollar-unit Sampling: A Practical Guide for Auditors. Both of the citation problems below have to be cleared before that lineage is used in print.

The standard's header reads "(Effective for audits of financial statements for periods beginning on or after December 15, 2021)". Two introductory paragraphs carry the dates.

CAS 315, paragraph 10 Introductory Periods beginning on or after 15 Dec 2021

This CAS is effective for audits of financial statements for periods beginning on or after December 15, 2021.

CAS 315, paragraph 10A Introductory Para 35: periods beginning on or after 15 Dec 2026

The issuance of CAS 240, The Auditor's Responsibilities Relating to Fraud in an Audit of Financial Statements, gave rise to conforming amendments in paragraph 35. Paragraph 35 is effective for audits of financial statements for periods beginning on or after December 15, 2026.

7.1 What changed

The change is documented in the CPA Canada Handbook – Assurance Highlight Summary No. 29, May 2020, which states that revised CAS 315 "revises and replaces existing CAS 315, Identifying and Assessing the Risks of Material Misstatement through Understanding the Entity and Its Environment" and then lists the changes.

Handbook – Assurance Highlight Summary No. 29 Highlight Summary May 2020

• clarifies the definition of 'significant risk' and explicitly introduces the concept of spectrum of inherent risk to assist the auditor in making a judgment, based on the likelihood and magnitude of a possible misstatement, on a range from higher to lower, when assessing risks of material misstatement;
• introduces the concept of inherent risk factors, including complexity, subjectivity, change, uncertainty or susceptibility to misstatement due to management bias or other fraud risk factors insofar as they affect inherent risk;
• introduces the concepts of 'significant classes of transactions, account balances and disclosures' and 'relevant assertions' to assist with the identification and assessment of the risk of material misstatement;
• separates the assessment of inherent and control risk;
• enhances the auditor's considerations in relation to the entity's use of information technology and how it affects the audit, and includes considerations for using automated tools and techniques in the application material;
• introduces a requirement to 'stand back' to evaluate the completeness of the significant classes of transactions, account balances and disclosures at the end of the risk assessment process;
• uses more explicit language and enhances requirements and application material to reinforce the importance of exercising professional skepticism when performing risk assessment procedures; and
• clarifies the threshold for identifying possible risks of material misstatement in CAS 200

Abridged. The bullets reproduced here are the ones that touch scoping and materiality.

The same summary confirms the effective date and lists the standards conformed: CAS 240 paragraphs 17, 21, 28 and 45; CAS 330 paragraphs 7-8, 10, 13-17 and 27; CAS 402 paragraphs 10-12 and 14; CAS 540 paragraphs 13, 16-17 and 19.

7.2 How it affects materiality-linked scoping

Three definitions in paragraph 12 build the scoping vocabulary. Relevant assertion feeds significant class, and significant risk sits on the inherent risk spectrum.

CAS 315, paragraph 12(h) Definition Periods beginning on or after 15 Dec 2021

Relevant assertions – An assertion about a class of transactions, account balance or disclosure is relevant when it has an identified risk of material misstatement. The determination of whether an assertion is a relevant assertion is made before consideration of any related controls (i.e., the inherent risk). (Ref: Para. A9)

CAS 315, paragraph 12(k) Definition Periods beginning on or after 15 Dec 2021

Significant class of transactions, account balance or disclosure – A class of transactions, account balance or disclosure for which there is one or more relevant assertions.

CAS 315, paragraph 12(l) Definition Periods beginning on or after 15 Dec 2021

Significant risk – An identified risk of material misstatement: (Ref: Para. A10)

• For which the assessment of inherent risk is close to the upper end of the spectrum of inherent risk due to the degree to which inherent risk factors affect the combination of the likelihood of a misstatement occurring and the magnitude of the potential misstatement should that misstatement occur

Partial. The stem and limb (i) only.

CAS 315, paragraph 29 Requirement Periods beginning on or after 15 Dec 2021

The auditor shall determine the relevant assertions and the related significant classes of transactions, account balances and disclosures. (Ref: Para. A202-A204)

CAS 315, paragraph A202 Application material Periods beginning on or after 15 Dec 2021

Determining relevant assertions and the significant classes of transactions, account balances and disclosures provides the basis for the scope of the auditor's understanding of the entity's information system required to be obtained in accordance with paragraph 25(a).

CAS 315, paragraph 34 Requirement Periods beginning on or after 15 Dec 2021

If the auditor plans to test the operating effectiveness of controls, the auditor shall assess control risk. If the auditor does not plan to test the operating effectiveness of controls, the auditor's assessment of control risk shall be such that the assessment of the risk of material misstatement is the same as the assessment of inherent risk.

The stand-back

CAS 315, paragraph 36 Requirement Periods beginning on or after 15 Dec 2021

For material classes of transactions, account balances or disclosures that have not been determined to be significant classes of transactions, account balances or disclosures, the auditor shall evaluate whether the auditor's determination remains appropriate. (Ref: Para. A233-A235)

CAS 315, paragraph A233 Application material Periods beginning on or after 15 Dec 2021

As explained in CAS 320, materiality and audit risk are considered when identifying and assessing the risks of material misstatement in classes of transactions, account balances and disclosures. The auditor's determination of materiality is a matter of professional judgment, and is affected by the auditor's perception of the financial information needs of users of the financial statements. For the purpose of this CAS and paragraph 18 of CAS 330, classes of transactions, account balances or disclosures are material if omitting, misstating or obscuring information about them could reasonably be expected to influence the economic decisions of users taken on the basis of the financial statements as a whole.

The tie-back. This is the paragraph that connects the scoping architecture to materiality, and it is the one to quote.

CAS 315, paragraph A234 Application material Periods beginning on or after 15 Dec 2021

There may be classes of transactions, account balances or disclosures that are material but have not been determined to be significant classes of transactions, account balances or disclosures (i.e., there are no relevant assertions identified).

7.3 The one Canadian amendment

CAS 315 appears in the Preface Appendix 2 summary table with a single amended paragraph, CA56. A C prefix on a paragraph number is the detection rule: it means Canada changed it.

CAS 315, paragraph CA56 Canada Application material Periods beginning on or after 15 Dec 2021

An understanding of the entity's organizational structure and ownership may enable the auditor to understand such matters as:

Opening only. CA56 is the only Canadian amendment listed for CAS 315, it is application material, and it has nothing to do with materiality or scoping thresholds.

8.1 Where this sits in the Handbook

The path is CPA Canada Handbook – Assurance → Handbook → Canadian Auditing Standards → CAS 320 / 450 / 530 / 315. The sibling top-level nodes under Assurance/Handbook are the Preface, the Glossary of Terms, Canadian Standards on Quality Management, Other Canadian Standards, Assurance and Related Services Guidelines, and Archived Pronouncements.

The governing document for everything in this section is the Preface to the CPA Canada Handbook – Assurance, Knotia document ID BNaE870VbQUGs9eKq8ev3Dg, marked "(Effective as of July 1, 2026)". The Handbook collection is "Revised to: Update No. 51 (07/26)".

Preface, paragraph 11 Preface Effective as of 1 July 2026

The CASs constitute GAAS for audits of financial statements and other historical financial information.

Preface paragraph 17 confirms that incorporating legislation requiring audits "in accordance with generally accepted auditing standards, the primary source of which is the CICA Handbook" is satisfied by performing the audit in accordance with the CASs.

8.2 How CAS numbering maps to the ISAs

Preface, paragraph 19 Preface Effective as of 1 July 2026

CASs result from the adoption of International Standards on Auditing (ISAs), developed and issued by the IAASB, that are consistent with the International Framework for Assurance Engagements and are to be applied in the audit of financial statements and other historical financial information. The AASB makes changes to the wording of the ISAs that do not affect how a practitioner performs an audit of financial statements or other historical financial information, so that the CASs can be used in the context of the Assurance Handbook. These changes are set out in Appendix 3.

Preface, Appendix 3 Preface Effective as of 1 July 2026

The terms 'Glossary of Terms issued by the IAASB,' 'IAASB,' 'ISA,' and 'ISAs,' are replaced by the terms 'Glossary of Terms in the Assurance Handbook,' 'AASB,' 'CAS,' and 'CASs,' respectively.

In Canada, governing legislation often requires the use of (and it is generally accepted practice to use) the phrase 'present fairly, in all material respects.'

Two substitutions. The first is mechanical vocabulary. The second is why "present fairly, in all material respects" is used throughout in place of the ISA alternative "give a true and fair view".

Preface, paragraph 20 Preface Effective as of 1 July 2026

The AASB may make amendments to ISAs that do affect how a practitioner performs an audit of financial statements or change the effective date of application of ISAs, in accordance with criteria that the AASB has developed ... When amendments are made, they are clearly identified in the Assurance Handbook by adding an explanation at the beginning of the standard and by adding the letter C at the start of the amended paragraph or footnote number. New paragraphs or footnotes are also uniquely identified. Appendix 2 lists the CASs that include amendments made by the AASB when adopting the respective ISAs.

Preface, paragraph 21 Preface Effective as of 1 July 2026

In some circumstances, an auditor performing an audit in accordance with the CASs may also wish to represent compliance with the ISAs. The CASs contain the ISAs issued by the IAASB together with any amendments made by the AASB in accordance with the criteria set out in Appendix 1. Compliance with the CASs relevant to the engagement will not necessarily result in compliance with the ISAs relevant to the engagement. Appendix 2 provides, for each amendment that has been made when adopting ISAs, its effect on the ability of the practitioner performing an audit of financial statements in accordance with the CASs to also comply with the ISAs.

8.3 Canadian departures affecting the four standards in this pack

C2A falls into Appendix 2 item 7, the deferred effective date category. That item is the one to quote, because it says what a deferred date costs.

Preface, Appendix 2, item 7 Preface Effective as of 1 July 2026

Amendment. The effective dates of certain Canadian standards adopted from international standards differ from those in the corresponding international standard. The applicable Canadian standards are included in the summary table.

Reason. The AASB has deferred the effective dates to facilitate an orderly implementation of the standards.

Effect on compliance with international standards. These amendments will prevent an engagement performed in accordance with Canadian standards from being in compliance with the equivalent international standards. A practitioner performing an engagement under each of the applicable standards should not represent compliance with the corresponding international standards unless it complies with all the requirements in the international standard.

8.4 Less complex entities

Canada has not adopted the ISA for LCE, and the Preface says so in terms.

Preface, Appendix 2, item 10 Preface Effective as of 1 July 2026

Amendment. References in IAASB standards to the IAASB's ISA for LCE are not included in the equivalent Canadian standards. The wording in the international standards provide options (i.e., an assurance engagement may be conducted using ISAs, the ISA for LCE or ISAEs). Practitioners performing engagements in accordance with Canadian standards do not have the same options. Therefore, for this Canadian amendment only, the paragraphs have not been marked with a 'C' and the IAASB wording is not shown in square brackets in the equivalent Canadian standard.

Reason. The AASB has not adopted the ISA for LCE in Canada.

Effect on compliance with international standards. The amendment does not prevent an engagement performed in accordance with the Canadian standards from being in compliance with the equivalent international standards.

AASB project page, "ISA for LCE", frascanada.ca Standard setter website Retrieved 21 August 2026

The AASB decided not to adopt the IAASB's ISA for LCE as it was determined to not be in the Canadian public interest. The AASB will continue to explore possible Canadian solutions.

AASB project page, "Audits of Less Complex Entities", frascanada.ca Standard setter website Retrieved 21 August 2026

In response, in January 2025 the AASB established the Audits of Less Complex Entities Working Group, a multidisciplinary group with broad membership from across the LCE audit ecosystem.

What the Group does. Responding to LCE audit issues including practical guidance, influencing scalability in the CASs, and monitoring emerging issues.

The Group's anticipated timeline lists "Publish Guidance on Journal Entry Testing" in Q3 2026, and providing feedback on the Audit Evidence and Risk Response and ISA 500 Series exposure drafts.

8.5 Current status: what is in force, what is coming, what is under exposure draft

The international side

IAASB, "Latest On Our Projects", iaasb.org International Standard setter website Retrieved 21 August 2026

Active projects listed:

• Audit Evidence and Risk Response (exposure drafts approved June 2026, comment period opening early August 2026)
• ISA 500 Series
• ISA for LCE Maintenance
• ISSA 5000 implementation
• Modernizing ISRE 2410
• ISA 540 (Revised) post-implementation review
• Strategy and Work Plan 2028-2031
• Subject Matter-Specific Assurance Engagements
• Technology Position
• Technology: Quality Management

IAASB project archive, ISA 320 and ISA 450 International Standard setter website Retrieved 21 August 2026

In June 2008 the IAASB approved ISA 320 (Revised and Redrafted) and ISA 450 (Revised and Redrafted)

published in October 2008 after the Public Interest Oversight Board (PIOB) has confirmed that due process was followed in their development.

Two fragments. The approval sentence and the publication clause, from the archive entry for the clarity redraft. The project is recorded as closed.

9.1 Do materiality thresholds predict which misstatements get corrected

Choudhary, P., Merkley, K., and Schipper, K. (2019). "Auditors' Quantitative Materiality Judgments: Properties and Implications for Financial Reporting Reliability." Journal of Accounting Research 57 (5): 1303-1351. DOI 10.1111/1475-679X.12286. United States data. The data source is the actual materiality amounts auditors reported to the PCAOB during inspections.

Choudhary, Merkley and Schipper, JAR 57 (5): 1303-1351 United States Academic Published 2019

Findings, quoted from the PCAOB's own summary page for the paper:

• Auditors' decisions "do not appear to result simply from applying conventional rules-of-thumb, (e.g., 5% of pre-tax income)."
• Judgments are "associated with size-related financial statement outcomes (income, revenues and assets), where the relative importance of the size-related outcomes varies with client characteristics such as financial performance."
• "looser materiality is associated with fewer audit hours and lower audit fees", and with "lower amounts of proposed audit adjustments and, in extreme cases, with a greater incidence of restatements."

Second-hand. The three findings above are quoted from the PCAOB's published-paper summary page, not from the article.

Other papers identified but not retrieved

9.2 Canadian regulator inspection findings: CPAB

The honest answer is that CPAB does not report materiality determination as an inspection finding theme. The reports checked, with what each one inspected:

The 2025 Annual Report breaks its 27 findings down further: 10 significant findings in 62 files at the four largest firms (16 percent); 4 in 31 files at other annually inspected firms (13 percent); 13 in 27 files at non-annually inspected firms (48 percent). In the 2024 Annual Report, no materiality, performance materiality, sampling or misstatement-evaluation finding theme appears.

The recurring themes CPAB does report

• 2024 Interim Insights, October 2024: identifying and assessing the risks of material misstatement; use of an auditor's expert; fraud; supervision and review; ethical requirements including independence; compliance with licensing requirements.
• 2025 Interim Insights, October 2025: technology used in audits; identification and response to fraud risks; audits of group financial statements; evaluation of accounting policies.
• 2025 Annual Report, March 2026, eleven themes: identifying and assessing risks of material misstatement; evaluating the entity's accounting policies; evaluating audit evidence; auditing accounting estimates; use of an auditor's expert; ethical requirements including independence; audit documentation, supervision and review; identification and response to fraud risks; services provided by a service organization; technology used in audits; audits of group financial statements. No materiality-determination theme.

The closest CPAB comes to the subject is a group-audit reference in the 2024 interim report:

CPAB, 2024 Interim Inspections Results Canada Regulator report October 2024

"the aggregation risk that undetected misstatements in components not subject to audit procedures may exceed materiality for the financial statements as a whole"

Not what it looks like. This is a group-audit point rather than a materiality-determination point.

9.3 PCAOB, for comparison

9.4 Non-Canadian regulator work directly on materiality determination

Both of these are already used in section 3, and both are worth citing again here as inspection-adjacent evidence, both clearly labelled non-Canadian.

FRC, Audit Quality Thematic Review: Materiality United Kingdom Regulator report December 2017

8 firms and 32 audits, with the finding that materiality set by some firms "could be around 100% higher" than others.

CEAOB, Report on the CEAOB Survey: Materiality in the Context of an Audit European Union / EEA Regulator report July 2022

495 public interest entity audit files across 21 EEA countries.