Structured Interview — Standardized Interview for Survey Research

Both use the same fixed set of questions, but in a questionnaire the respondent reads and answers without an interviewer, while in a structured interview a trained interviewer reads the questions aloud and records the responses. The interview format increases accessibility for low-literacy respondents, reduces item non-response, and enables clarification of mechanical misunderstandings, but at greater cost per respondent.

Yes, but open-ended questions in a structured interview are typically brief and followed by a pre-specified code frame applied by the interviewer or analyst. If the goal is extended narrative or exploratory probing, a semi-structured or in-depth interview is more appropriate, as they allow the interviewer to follow up flexibly on participant responses.

Sample size depends on the research question and planned analysis, not on the interview format itself. Because structured interviews are typically used for quantitative generalization, the logic of probability sampling applies: the sample must be large enough to yield adequate precision for the key estimates and subgroup comparisons. Dozens to thousands of participants are common; the target is statistical power, not thematic saturation.

In a structured interview every question and its wording are fixed, probes are scripted, and the interviewer does not deviate. In a semi-structured interview there is a topic guide with core questions, but the interviewer can rephrase, reorder, and probe flexibly in response to the participant's answers. Structured interviews maximize comparability; semi-structured interviews maximize depth and discovery.

It can be, but care is required. Interviewer presence can reduce social desirability bias compared to self-administered formats for some topics, but for highly sensitive matters (e.g., sexual behavior, illicit drug use) self-administered formats or audio computer-assisted self-interview (ACASI) often yield more candid responses. The structured format provides no conversational space for participants to raise issues on their own terms.