Item Non Response

TL;DR

• Occurs when a respondent skips or declines to answer an individual survey question for reasons such as lack of understanding, lack of information, or unwillingness.
• Can reduce accuracy and reliability of survey results and introduce bias if non-response is systematic across groups.
• Manageable through careful survey design (fewer or better-targeted questions, avoiding redundancy), using open-ended formats where appropriate, and applying imputation to estimate missing values.

Definition

Item non-response refers to the failure to provide a response to a specific question or item on a survey or questionnaire.

Explanation

Item non-response can arise because a respondent does not understand a question, does not have the necessary information to answer, or does not want to answer. When many respondents omit the same item, it becomes difficult to represent the population accurately or draw meaningful conclusions. Non-random patterns of item non-response—where certain groups are more likely to skip particular items—can introduce bias into survey estimates. Researchers address item non-response by designing shorter and clearer questionnaires, preferring question formats that elicit answers, and using statistical techniques to fill in missing values.

Examples

Income question

A survey asking respondents to provide their income may encounter item non-response when individuals are unwilling to disclose financial information or do not have a stable income, resulting in no answer for that question.

Drug use question

A survey about drug use that asks whether a respondent has used a specific drug may receive no response from individuals who have never used that drug, producing item non-response for that item.

Notes or pitfalls

• Large amounts of item non-response make it difficult to accurately represent the target population and to draw reliable conclusions.
• If non-response is correlated with respondent characteristics, survey results can be biased.
• Imputation can be used to estimate missing values by leveraging responses from other participants, but it relies on statistical assumptions and should be applied carefully.
• Minimizing the number of questions, avoiding redundancy, and using question formats that make it easier for respondents to answer can reduce item non-response.

Related terms

• Imputation
• Open-ended questions
• Closed-ended questions
• Survey design
• Missing data
• Bias