Sampling Method
MUS is standard for substantive overstatement testing. Classical is used when items are similar in size or when testing for understatement.
↳ ISA 530.A4 — items are selected proportional to their monetary value. Larger items have a higher probability of selection. Standard for overstatement testing.
Confidence Level
Reflects the assessed risk of material misstatement. Higher confidence = larger sample.
↳ Risk of incorrect acceptance: 10%. Confidence factor (CF): 2.31.
Population & Materiality
Enter the total monetary value of the population being sampled and the materiality thresholds from your planning.
Total monetary value of the account or class of transactions
Typically performance materiality or a fraction of it
Prior year misstatements or current estimate. Leave blank or enter 0 if none.
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Sampling Considerations for Government
Government and public sector audits have a dual objective: providing an opinion on the financial statements and assessing compliance with laws, regulations, and budget appropriations. Sampling design must address both objectives. Expenditure populations are typically very large, and public accountability demands high confidence levels that translate to larger sample sizes.
Sampling focus: Government
Expenditure sampling is the primary focus of government audits. MUS applied to the population of payments and commitments ensures coverage of the largest expenditures, while attribute sampling is used to test compliance with procurement regulations, approval hierarchies, and budget authority. Revenue sampling focuses on tax or fee collection accuracy and completeness.
Key sampling considerations
Compliance testing requires attribute sampling with defined confidence levels — regulators and oversight bodies often specify minimum sample sizes or confidence levels for compliance audit work. Procurement regulation compliance should be tested using a separate sample — verify that competitive bidding thresholds, approval requirements, and contract award procedures were followed. Budget appropriation compliance requires testing that expenditure does not exceed authorised amounts at the appropriation level — sample transactions across budget lines. Grant programme expenditure passed through to sub-recipients should be sampled to verify that the sub-recipient met eligibility requirements and programme conditions. Payroll is often the largest expenditure category — sample employee records to verify existence, pay rate authorisation, and correct classification between departments and programmes.
ISA 530.5 — Audit sampling means applying audit procedures to less than 100% of items within a population so that all sampling units have a chance of selection.
ISA 530.A4 — MUS uses monetary units as the sampling unit, giving each monetary unit an equal probability of selection.
ISA 530.A11 — Sample size is affected by the tolerable misstatement, expected misstatement, and the required level of confidence.