Open-Ended Questions in Science-Based Interviewing

C. Edward
Jun 20, 2023
3 min read

Updated: Jan 12

In Science-Based Interviewing (SBI), few techniques influence interview quality as reliably as open-ended questions. When paired with rapport and active listening skills, such as appropriate pauses, labeling, reflections, and affirmations, open-ended questions consistently produce more information and higher-quality information. This aligns with ixi's information-supremacy philosophy: more and more accurate information, because relevant data improves decisions, investigations, and outcomes. More information is better than less, every single time.

What is an Open-Ended Question?

An open-ended question invites more than a short or one-word reply. Instead, it encourages the interviewee to respond with a narrative in their words. Questions such as “Tell me what happened,” or “Describe the individual,” allow people to share details, context, emotions, and reasoning without being constrained by predefined or multiple-choice (leading question) answer choices.

In investigative interviews, open-ended questions are foundational because they elicit free narratives. These narratives give investigators opportunities to learn unknown unknowns, information the interviewer could not anticipate or even know to ask about in advance. Because this information was outside the investigator’s frame of reference, it allows the interviewer to be genuinely surprised, opening the door to new follow-up questions, new lines of inquiry, and substantially more case-relevant data than closed, confirmatory, or leading questions would ever reveal.

Open-Ended Questions: An Opening to Understanding

Interviews should begin with open-ended questions. Unlike closed, confirmatory, or leading questions, which restrict responses and subtly steer answers, open-ended questions maximize information flow to the investigator.

Research from Pew Research Center illustrates this clearly. During the 2008 presidential election, when respondents were given a closed-ended option that explicitly listed “the economy,” over half selected it. When asked the same question in an open-ended format, only 35% mentioned the economy. Notably, 43% of respondents provided answers that did not appear in the closed-ended version at all. Open-ended questions revealed perspectives that researchers would not have otherwise captured.

This finding translates directly to investigative interviews: you only learn what you allow people to tell you.

Open-ended questions & science-based interviewing — Open-ended questions are the engine that drives Science-Based interviewing.

Open-Ended Questions Drive Science-Based Interviewing

Open-ended questions are the engine of science-based interviewing. Closed, confirmatory, or leading questions tend to reflect the interviewer’s assumptions—often reinforcing confirmation bias. In contrast, open-ended questions place the interviewer in discovery mode.

This is where the “unknown unknowns” emerge: information that exists outside the investigator’s current hypotheses. These unexpected details reshape understanding, generate better follow-up questions, and open entirely new investigative avenues. Skilled investigators thrive here—not by confirming what they believe, but by learning what they did not yet know to ask.

If justice is the goal, interviews cannot be about validating beliefs. They must be about discovering truth, demonstrated through your interviewing method, not marketing.

Field research reinforces this point. Open-ended questions elicit responses that are, on average, six times longer than probing questions and nine times longer than yes–no questions. Yet despite their effectiveness, open-ended questions made up less than 1% of all questions in a study of real police interviews and were entirely absent in more than 60% of them (Snook et al., 2012).

ED Questions: A Practical Framework

TED questions—Tell, Explain, Describe—are a simple, effective way to ensure open-ended questioning remains central to the interview.

T.E.D. Question Starters

Tell me what happened.
Explain how that unfolded.
Describe what you noticed.

TED questions invite broad, uninterrupted narratives. They give interviewees latitude to share details about timelines, actions, relationships, and decision points, often revealing critical information the interviewer did not anticipate. Beginning interviews and new topics with TED questions increases both the quantity and relevance of case information.

Curiosity and Information Elicitation

Once open-ended questions surface new information, something important happens: the interview gains direction without being forced. Each narrative response highlights new topics, clarifies priorities, and guides more focused—but still open—follow-up questions.

By remaining curious and resisting the urge to steer or confirm, investigators create conditions where accurate information emerges organically. Neutral, well-timed open-ended questions allow truth to surface without coercion, distortion, or premature conclusions.

Conclusion

Open-ended questions are not merely a technique, they reflect a science-based interviewing mindset. When used deliberately, they uncover unanticipated details, protect against bias, and lead to more accurate, complete, and defensible information.

Coupled with curiosity, rapport, and active listening, open-ended questions allow the interviewee to guide the narrative while the investigator guides the process. The result is better information, more information, stronger cases, reduced risk, and fewer investigative errors. Science-Based Interviewing begins, and is sustained, by asking better open-ended questions.