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    Nonresponse Bias

    Nonresponse bias occurs when the people who do not respond to a survey differ systematically from those who do, on the variable being measured.

    Nonresponse bias is a specific form of selection bias and the single biggest threat to validity in customer surveys. It is not the same as low response rate: a 5% response rate can be unbiased if non-responders are similar to responders, and a 70% response rate can be heavily biased if the 30% missing are systematically different. Diagnose nonresponse bias by comparing responder vs non-responder traits using internal data (tenure, plan, activity, geography), and by following up with a small non-responder sub-study. Apply post-stratification weighting when meaningful skew is detected.

    On sensitive HR and DEI topics, offering an anonymous survey lifts participation among reluctant respondents and helps close the gap that drives nonresponse bias.

    Example

    An HR survey gets 68% response in engineering but 31% in sales. The published 4.1/5 engagement score is heavily weighted toward engineering. Weighted to function distribution, true score = 3.6/5.

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    Related terms

    Selection Bias

    Selection bias is a systematic error arising when the people included in a survey differ from the target population in ways that affect the outcome.

    Survey Response Rate

    Response rate is the percentage of invited respondents who completed (or at least started) a survey.

    Response Bias

    Response bias is any systematic tendency of respondents to answer questions inaccurately, either intentionally or unconsciously.

    Convenience Sampling

    Convenience sampling recruits whoever is easiest to reach — website visitors, email-list subscribers, social-media followers — and is the dominant approach in commercial surveys despite its limitations.

    Random Sampling

    Random sampling is a probability sampling method where every member of the target population has an equal, known chance of being selected.

    Acquiescence Bias

    Acquiescence bias is the tendency of respondents to agree with statements regardless of their actual opinions.