If some form of statistical sampling method is used we can generally find a way of producing unbiased, or almost unbiased, samples and of evaluating objectively the errors identified. Provided that the use of statistical sampling is feasible and cost effective therefore, it should generally be used in preference to non-statistical methods. ... Monetary Unit Sampling (MUS) is a statistical sampling method in which a high value transaction is more likely to appear in the sample than one of low value.