Identify and discuss the differences between statistical and non-statistical sampling

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Identify and discuss the differences between statistical and non-statistical sampling


Sampling is a fundamental technique used by auditors to gather evidence efficiently and draw conclusions about entire populations. Within auditing, two primary approaches to sampling are statistical and non-statistical sampling. While both methods aim to achieve audit objectives, they differ significantly in their methodologies, applications, and interpretations of results. This article examines the distinctions between statistical and non-statistical sampling, highlighting their respective characteristics and discussing the circumstances in which each approach is utilized.

Statistical Sampling:

Statistical sampling involves the use of mathematical principles and techniques to select samples from a population in a systematic and random manner. The objective of statistical sampling is to provide auditors with a quantifiable level of confidence in the results obtained from the sample and allow for the extrapolation of those results to the entire population. Key characteristics of statistical sampling include:

Random Selection:

Samples are selected randomly from the population using statistical methods such as random number generators or systematic sampling techniques. This ensures that every item in the population has an equal chance of being selected, eliminating bias and ensuring the representativeness of the sample.

Quantifiable Results:

Statistical sampling provides auditors with quantifiable measures of sampling risk, such as confidence intervals and precision levels. By applying statistical formulas and calculations, auditors can determine the reliability and accuracy of sample results and assess the risk of making incorrect conclusions.

Sample Size Determination:

Statistical sampling requires the determination of an appropriate sample size based on factors such as population size, desired confidence level, and tolerable error rate. Sample size calculations are based on statistical principles and are designed to achieve a balance between accuracy and efficiency.

Non-Statistical Sampling:

Non-statistical sampling, also known as judgmental sampling, relies on the auditor’s judgment, experience, and expertise to select samples based on subjective criteria. Unlike statistical sampling, non-statistical sampling does not involve random selection or quantifiable measures of sampling risk. Instead, auditors use their professional judgment to determine sample size and select items they believe are most relevant to achieving audit objectives. Key characteristics of non-statistical sampling include:

Subjective Selection:

Samples are selected based on the auditor’s judgment and discretion, taking into account factors such as materiality, risk assessment, and audit objectives. Auditors may choose items they perceive to be high-risk, unusual, or representative of the population.

Qualitative Assessment:

Non-statistical sampling relies on qualitative assessments of sample results, rather than statistical measures of precision or confidence. Auditors evaluate sample findings based on their professional judgment and experience, considering factors such as consistency, completeness, and reasonableness.


Non-statistical sampling offers greater flexibility in sample selection and evaluation, allowing auditors to tailor their approach to specific audit objectives and circumstances. Auditors may adjust sample size and selection criteria based on emerging risks or changes in audit scope.

Differences and Considerations:

Objective vs. Subjective:

The primary distinction between statistical and non-statistical sampling lies in the objective nature of statistical sampling versus the subjective nature of non-statistical sampling. While statistical sampling relies on mathematical principles and random selection, non-statistical sampling relies on auditors’ judgment and discretion.

Quantifiable Measures vs. Qualitative Assessments:

Statistical sampling provides auditors with quantifiable measures of sampling risk and precision, whereas non-statistical sampling relies on qualitative assessments of sample results based on auditors’ professional judgment.

Efficiency vs. Flexibility:

Statistical sampling offers efficiency and precision in sample selection and evaluation but may require specialized knowledge of statistical techniques. Non-statistical sampling offers flexibility and adaptability but may be susceptible to bias and subjectivity.


In summary, statistical and non-statistical sampling represent two distinct approaches to sampling in auditing, each with its own set of characteristics, advantages, and considerations. While statistical sampling provides auditors with quantifiable measures of sampling risk and precision, non-statistical sampling offers flexibility and adaptability based on auditors’ judgment and expertise. Understanding the differences between these two approaches is essential for auditors to select the most appropriate sampling method based on audit objectives, resources, and the nature of the population being examined. By leveraging the strengths of both statistical and non-statistical sampling, auditors can gather evidence effectively, draw reliable conclusions, and provide stakeholders with confidence in the integrity of financial reporting.