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Sampling Error vs. Non-Sampling Error: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on February 15, 2024
Sampling Error variance in results due to using a sample instead of the entire population. Non-Sampling Error are errors in data collection not related to the sampling process.

Key Differences

Sampling error occurs when the sample does not perfectly represent the population, leading to variance between the sample estimate and the true population value. Non-sampling error, however, arises from other aspects of the research process, such as data collection errors, non-response, or faulty data processing.
Sampling error is inherent in the process of selecting a subset of the population and varies with the size and representativeness of the sample. Non-sampling error can occur in both sample surveys and censuses and is not affected by the sample size but by the quality of the survey design and execution.
The magnitude of sampling error decreases as the sample size increases, assuming a random sampling method. Non-sampling errors, conversely, can be present in any size of sample or even a full census, and their reduction depends largely on the quality control measures in place.
Sampling errors can be estimated and quantified through statistical methods, providing a measure of confidence in the results. Non-sampling errors are often more difficult to detect and quantify, as they can stem from a variety of sources in the data collection and processing stages.
Reducing sampling error typically involves increasing the sample size or improving sampling techniques. Reducing non-sampling error requires improvements in survey design, data collection methods, respondent selection, and data processing accuracy.

Comparison Chart

Source of Error

Selection of a subset of the population
Errors in data collection and processing

Dependence on Sample Size

Decreases with larger samples
Not directly related to sample size


Can be estimated and quantified statistically
Difficult to detect and quantify

Reduction Methods

Increase sample size or improve sampling methods
Improve survey design and execution


Inherent in any sampling process
Can occur in both sampling and non-sampling situations

Sampling Error and Non-Sampling Error Definitions

Sampling Error

The discrepancy between sample statistics and population parameters.
The sampling error led to an overestimation of the average income in our report.

Non-Sampling Error

Errors in data collection, processing, or analysis not related to sampling.
Mistakes in data entry were a significant source of non-sampling error in our study.

Sampling Error

The error caused by observing a sample instead of the whole population.
The difference in the actual population mean and our survey's mean is a sampling error.

Non-Sampling Error

Mistakes or biases in research not associated with the choice of the sample.
The non-response of selected participants was a major non-sampling error.

Sampling Error

Variability in survey results due to the sample's representativeness.
Due to sampling error, our study's results vary slightly from the national average.

Non-Sampling Error

Distortions in survey results arising from factors other than the sampling process.
Respondent misunderstanding of questions led to non-sampling errors.

Sampling Error

An error that occurs because the sample is not an exact replica of the population.
The small sample size contributed to a larger sampling error in our experiment.

Non-Sampling Error

Inaccuracies in research outcomes due to defective data collection methods.
The non-sampling error was caused by biased question phrasing in the survey.

Sampling Error

The difference in results caused by using a subset of a population for analysis.
Our poll's margin of error reflects the potential sampling error.

Non-Sampling Error

Errors resulting from issues in the operational aspects of a study.
Poorly trained interviewers introduced non-sampling errors into the survey results.


How can non-sampling error be minimized?

By improving survey design, data collection methods, and data processing.

Is sampling error present in a census?

No, as a census involves the entire population, not a sample.

What is sampling error?

It's the error that occurs due to using a sample of the population instead of the entire population.

Can sampling error be eliminated?

Not completely, but it can be reduced by increasing the sample size and using better sampling techniques.

Do non-sampling errors occur in a census?

Yes, they can occur in any data collection process, including a census.

What causes non-sampling error?

It's caused by factors like data collection errors, non-response rates, and processing mistakes.

How is sampling error measured?

It's usually measured by calculating the standard error or margin of error.

Can non-sampling errors be quantified easily?

They are often difficult to quantify due to their varied sources.

How does random sampling affect sampling error?

Random sampling can help reduce sampling error by ensuring representativeness.

Does increasing the sample size affect non-sampling error?

No, non-sampling errors are not directly related to sample size.

Can a biased sample lead to non-sampling error?

No, a biased sample typically results in sampling error.

What role does statistical significance play in sampling error?

It helps determine if the observed results are likely due to sampling error.

What impact does respondent behavior have on non-sampling error?

Respondent behavior, like non-response or misunderstanding questions, can significantly contribute to non-sampling error.

Can poor questionnaire design lead to non-sampling error?

Yes, it's a common source of non-sampling error.

Are processing errors considered non-sampling errors?

Yes, they fall under the category of non-sampling errors.

Does sampling error occur due to the method of data collection?

No, it's related to the choice and size of the sample.

Can sampling error be zero?

Theoretically, no, except when the entire population is surveyed.

What's a common example of sampling error?

Variance in public opinion poll results due to using a subset of the population.

Is interviewer bias a sampling or non-sampling error?

It's a non-sampling error.

Does data entry error contribute to non-sampling error?

Yes, it's a form of non-sampling error.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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