Semi-structured interview
A semi-structured interview is a qualitative interview that follows a prepared set of topics and core questions but lets the interviewer change the order, rephrase and add follow-up questions based on the participant's answers.
How it works
The interviewer works from a discussion guide listing the areas to cover and key questions, with suggested probes. Within that frame, they follow the conversation: asking for examples, exploring an unexpected comment, skipping what has been answered. Every participant covers the same core topics, so interviews can be compared, while each can go deeper where it matters.
It sits between the structured interview, with fixed questions in a fixed order, and the unstructured interview, a free conversation around a theme. Against the first, it gives up some comparability in exchange for depth; against the second, it gives up some freedom so that answers can be set side by side. Scribbr advises that it suits interviewers with some experience, since good follow-up questions are harder to ask on the spot than they look.
A worked example
An energy company runs 20 semi-structured interviews about switching suppliers, covering 5 topics in each. In interview 4, a participant mentions a smart meter that stopped working after a switch. The interviewer adds a probe on meters, and 9 of the remaining 16 describe the same fear.
Related
Automate this in Pulse
The fixed core of a semi-structured interview is the guide Pulse builds from the brief, and the flexible part is the moderator's follow-up whenever an answer needs more.