Non-sampling error (market research)

Non-sampling error is a broad term used in market research to describe any source of inaccuracy in research results that is not related to the process of selecting a sample. Unlike sampling error, which arises because only a subset of the population is measured, non-sampling errors can affect any research project, regardless of sample size.

Common sources of non-sampling error include:

Data entry mistakes: Human error when inputting responses into databases.
Measurement errors: Equipment malfunction, incorrect calibration, or 'zero errors' in counters or instruments.
Questionnaire design issues: Ambiguous, leading, or confusing questions that produce biased responses.
Non-response bias: Certain groups systematically not responding, skewing results.
Processing errors: Mistakes during coding, weighting, or tabulation of data.

Non-sampling errors can be systematic or random. Systematic errors, which are consistent and ongoing, are particularly difficult to detect because they may only become apparent after the data has been collected and analysed.

Why it matters

Non-sampling errors can significantly distort research findings, leading to incorrect conclusions or poor business decisions. Understanding and minimising these errors is critical for ensuring the accuracy and reliability of market research results.

DJS Research implements rigorous quality control procedures at every stage of a project – from questionnaire design, fieldwork, and data entry to processing and reporting – to reduce non-sampling error and maintain high standards of data integrity.

Why partner with DJS Research?

We build small, director-led, teams of sector experts who are with you from brief to debrief. As an employee-owned company, every one of us is invested in delivering quality, value, and long-term impact.

From agile testing to deep-dive strategic studies, we design research to meet your specific objectives. The agility of our in-house operations team and strength of our UK-wide recruiter network enable seamless execution at scale.

Our sector-focused teams have decades of experience understanding audiences and the complexities of the markets in which our clients operate. Working collaboratively we deliver actionable insight which drives positive change.

Non-sampling error (market research)

Non-sampling error (market research)

Why partner with DJS Research?

We are small enough. We are big enough. We are DJS Research

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