THE SHORT ANSWER
Probing questions invite greater detail or reasoning: what led to this, what supports it, what follows, and what else could explain it. Probe selectively, explain why you are asking, and let the response determine the next question.
Follow a depth ladder
Move from SURFACE ANSWER → REASON → EVIDENCE → CONSEQUENCE → ALTERNATIVE. You may stop at any step when the purpose is met.
| Move | Question |
|---|---|
| Reason | What makes you think that? |
| Evidence | What have you observed? |
| Context | What happened immediately before it? |
| Consequence | What happens if nothing changes? |
| Alternative | What else could explain this? |
Earn the follow-up by listening
Do not ask five probes at once. Reflect a key phrase, leave a pause, and choose the next question from the answer. GOV.UK interview guidance recommends open, neutral questions and simple follow-ups while avoiding rigid adherence to a discussion guide.
Evidence & context: GOV.UK Service Manual
Deep questions invite explanation
The National Academies describes elaborative interrogation as asking why, how, what-if and what-if-not questions that invite deeper reasoning. The evidence is promising but context-dependent; a deep-sounding question is not useful when the learner lacks the knowledge needed to answer it.
Offer a source, example or smaller prompt when the question creates blankness rather than productive thought.
Evidence & context: National Academies of Sciences, Engineering, and Medicine
Use the two-probe limit
In one conversation, ask an initial open question and no more than two genuine follow-ups before summarising what you heard. Then ask whether your summary is accurate. Review whether each probe responded to the person or to your prepared script.
Sources & further reading
- Using In-Depth Interviews
GOV.UK Service Manual. Practical public-service guidance on research questions, neutral prompts, follow-up questions, consent and listening. It is professional guidance rather than experimental evidence and must be adapted to the research context.
- How People Learn II: Learners, Contexts, and Cultures
National Academies of Sciences, Engineering, and Medicine. A 2018 consensus synthesis covering metacognition, self-regulation, explanation and deep-reasoning questions. Findings vary by learner, task and context; the report does not imply that asking any question improves learning.
Examples and exercises are illustrative unless attributed to a source. No independent expert review is claimed.
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