Monetary Unit Sampling (MUS)
Definition
A probability-proportional-to-size method that treats each currency unit in the population as a sampling unit. Larger transactions have a higher probability of selection. Results are expressed as an upper error limit in currency, making them easier to evaluate against a materiality threshold.
- Also called
- Probability-proportional-to-size (PPS) sampling
- Sampling unit
- Each individual currency unit
- Selection bias
- Larger transactions more likely selected
- Output
- Upper error limit in currency terms
Common questions
Why is MUS particularly suited to detecting overstatement in fraud audits?+
Because selection probability scales with transaction size, MUS naturally concentrates audit attention on the largest-value items, which is exactly where a material overstatement is most likely to reside and most costly if missed.
What is a limitation of monetary unit sampling in fraud investigations?+
MUS is weak at detecting understatement errors or omitted transactions, since a transaction that was never recorded, or was recorded at a value near zero, has little or no chance of being selected by a size-weighted method.
Related terms
- Attribute Sampling
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- Confidence Level
- An explicit label attached to an attribution assessment indicating how strongly the available evidence supports the conclusion. Standard tiers are low, medium,...
- Risk-Directed Selection
- A judgmental sampling approach in which items are chosen because they exhibit specific risk indicators: unusual amounts, unusual payees, bypass of normal...
- Stratified Sampling
- A sampling design that divides the population into homogeneous subgroups (strata) and samples each stratum separately. Allows the auditor to apply higher...
- Tolerable Deviation Rate (TDR)
- The maximum rate of control deviations the auditor is willing to accept before concluding that a control cannot be relied upon. Setting...