Science-Based Interviewing: The Power of Open-Ended Questions

In the world of science-based interviewing, certain techniques can significantly influence the effectiveness of your interviews and interrogations. Among these, there are many variations; one of the most prominent ones is asking open-ended questions coupled with nodding your head. Research supports the use of these questioning strategies, demonstrating how they contribute to the information supremacy philosophy, which means not only more information but also better quality information elicited during your interviews. More information is better than less, every single time.

What is an Open-Ended Question?

An open-ended question is one that invites more than a brief reply, such as a single word or short phrase, and instead encourages interviewees to elaborate in their own words. These questions should prompt respondents to provide detailed information, perspectives, emotions, and reasoning, rather than simply selecting from predetermined options. For example, asking “What led you to that decision?” or “Tell me what happened?” allows interviewees to share detailed responses with more information and context. In investigative settings, open-ended questions are valuable because they elicit the respondent’s explanatory model and deeper understanding, helping uncover insights that closed questions will miss altogether.

Open-Ended Questions: An Opening to Understanding

Open-ended questions are an incredible tool in any interview. The interview should start with open-ended questions. They allow respondents to provide a narrative response in their own words rather than picking from a predetermined list of answer choices (leading questions), which will restrict the amount of information you receive. Pew Research Center notes the power of open-ended questions through an example from the 2008 presidential election. When respondents were explicitly offered "the economy" as a response option, over half chose it. Yet, when asked the same question in an open-ended format, only 35% mentioned the economy. Importantly, 43% of those who responded to the open-ended question gave a response not listed in the closed-ended version, highlighting the capacity of open-ended questions to reveal unanticipated perspectives and insights (Pew Research Center, n.d.).

Open-ended questions are the engine that drives science-based interviewing.

This election example translates directly to the interview and interrogation room: when you rely solely on closed, confirmatory, or leading questions, you risk boxing the person into predefined narratives, often your own predefined narratives (confirmation bias), ones you’ve already imagined or assumed. On the other hand, when you use open-ended questions, you step into a mode of discovery. This is where the "unknown-unknowns" live—those pieces of information that aren’t just missing but entirely outside your frame of reference until the interviewee brings them forward. It’s in this space that skilled investigators thrive, not by confirming what they think they know, but by learning what they didn’t even realize they needed to ask. This is apex curiosity. Each unexpected detail will reshape your understanding of the situation, sharpen your follow-up questions, often unlock entirely new lines of inquiry, and allow you to make more informed investigative decisions.

Curious investigators ignite their information-laden investigations by asking open-ended questions that don’t just fill in gaps; they uncover what no one even knew to look for. It’s where elite investigators separate themselves from the routine ranks. Open-ended questions ignite the process of deep discovery. If it's really about justice, it can't be about confirming your beliefs; it must be about finding the truth. You should demonstrate your commitment to truth and justice not in your marketing, but during the interview process. In action.

Open-ended questions are the engine that drives science-based interviewing. Field research has shown that open-ended questions elicit responses that are significantly longer and more informative, on average, six times longer than probing questions and nine times longer than closed yes–no questions. Despite their power, open-ended questions made up less than 1% of all questions asked in a study of real police interviews and were completely absent in over 60% of the interviews analyzed (Snook et al., 2012).

Curious investigators ignite their information-laden investigations by asking open-ended questions that don’t just fill in gaps or boxes on a standard report; they uncover what no one even knew to look for. It’s where elite investigators separate themselves from the routine ranks of "just the facts." If it's really about justice, it can't be about confirming your beliefs; it must be about actually finding the truth (not just putting it in your marketing materials). You should demonstrate your commitment to truth and justice in your interview methods, not in your marketing material. In action.

Eliciting information: Curiosity

Once you’ve uncovered new information or the unknown unknowns through your first open-ended questions at the start of an interview, something powerful happens, you begin to see new topics, objectives, and avenues for more inquiry. Each unfiltered response becomes a gateway to more informed, targeted open-ended questions, allowing you to explore areas of relevance or concern, some you hadn’t anticipated. This approach builds a information-laden, more accurate understanding of the incident. By staying curious and deliberately leaving space for the person to speak freely, you resist the urge to steer, confirm, or rush the process. With well-constructed, neutral open-ended questions, you're creating conditions that let truth rise to the surface on its own.

Conclusion

Open-ended questions aren’t just a technique, they’re part of the science-based interviewing mindset. When used properly, they uncover the unknown, reveal unanticipated details, and open the door to deeper, more meaningful interviews. By staying curious and allowing the interviewee to guide the narrative, investigators gather more accurate, relevant, and complete information, leading to better decisions, stronger cases, less risk, and fewer mistakes.

Pew Research Center. (n.d.). Writing Survey Questions. Retrieved from https://www.pewresearch.org/methods/u-s-survey-research/questionnaire-design 

Snook, B., Luther, K., Quinlan, H., & Milne, R. (2012). Let ’em talk! A field study of police questioning practices of suspects and accused persons. Criminal Justice and Behavior, 39(10), 1328–1339. https://doi.org/10.1177/0093854812449216