Non-Statistical Sampling is the method of evaluation the competence of the evidence gathered from the auditor. Selected-sample size is referred to as non-statistical sampling. There are two acceptable methods used for projecting the amount of misstatements. They are ratio projection and difference projection.
Ratio projection is used in the non-statistical sampling and classical variable statistical sampling. It projects the misstatement amount by dividing the amount of misstatement and percentage of the dollars of the sample population.
Difference projection is defined as the average misstatements of each and every item in the sample to the overall population. This projection is executed when the misstatement is stable for the entire item, though its dollar size varies.
Results arrived from these two projections are identical, when the same proportion of items in the populations are incorporated in the sample. But, when different proportions are arrived at, then the choice between the two is based on the auditor’s judgment.