An Interview Is Not a Sandwich...and other reflections on qualitative interview structures
Updated: 5 days ago
How to choose between structured, semi-structured, and unstructured interviews, and run each one well
Part 2 of our interviewing series: Should You Interview? · An Interview Is Not a Sandwich (this) · Classic Interview Blunders · Don’t Interview in Sandals
Last updated: October 2026
An interview is not a sandwich. There is more to an interview structure than a stack of meaty middle topics sandwiched between “can you tell me about yourself?” and “is there anything else you’d like to share?”
A good interview structure depends on the goal of the conversation. Too often, interviewers create the same design over and over again based on convenience rather than what makes sense for the context. While a go-to structure can be a useful starting point for learning and building confidence, a high-quality interview requires more thoughtfulness than just slotting new questions into an old template.
Drawing on lessons learned from our experience conducting over 500 interviews and focus groups, we reflect on and share tips for structuring evaluation interviews. In doing so, we answer these questions:
What is a structured interview?
What is a semi-structured interview?
What is an unstructured interview?
How do you choose between structured, semi-structured, and unstructured interviews?
What is a structured interview?
The structured interview is like a corndog. It centres on a rigid frame to ensure consistency. Like a corndog at a fair, the structured interview is a crowd-pleaser that works best when the primary goal is to reach a large group. Questions are organized around a few key topics or themes related to the evaluation. Every participant is asked the same question in the same way to create a standardized set of comparable answers.
When should you use a structured interview?
Typically, this interview is used with a large group when little variation between reflections on a particular topic is anticipated. Brief responses illustrate a range of expected or unexpected experiences (e.g., what patients think is working or not working in a hospital unit).
How do you conduct a structured interview?
To gather a narrow range of answers from a large group, structured interviews must be focused. Get to the point with direct “what” or “how” questions for a few key evaluation themes or topics. Interviewees talk through what happened and briefly explain their experiences.
For example, suppose one key theme is about the accessibility of care in a hospital unit. In that case, you might ask a direct question, “What was it like for you to access care in this hospital unit?” Then, you might follow up with either a specifying question, “Can you recall which specific steps you took to gain access to care?” or a prompt, “Can you give me an example of one thing that made care accessible for you?”
Because the structured interview can come across as more formal, we ask only a few things about each theme before moving on to avoid exhausting the interviewee. Our style is to keep it light, catch a glimpse of something, and move on. We also practice our questions with each other ahead of time to ensure that there is a good balance between topics, the questions are answerable, and we resist the urge to improvise a follow-up prompt.
Pro tip:
The most challenging thing about the structured interview is just reading the question verbatim with a similar tone every time. So, it is a good idea to get each question right during the planning stage to avoid the need to ask clarifying or follow-up questions. Then, just sit on your hands and resist the urge to prompt.
What is a semi-structured interview?
The semi-structured interview is like a burger. Variations in the bun, patty, toppings, and sauces are expected but still count as burgers. It depends on who makes it, who orders it, and when. Like a burger, this interview structure works when the primary goal is to create preferable options for a reasonable number of people.
In a semi-structured interview, questions are organized around a few key topics or themes related to the evaluation. But, unlike the structured interview, variation is allowed.
When should you use a semi-structured interview?
Typically, this interview is used with a smaller group of people when the goal is to explore a few themes in more depth and detail. There may be some expectation that responses can be compared across participants. The human element may be of interest, too, when all those “it depends” answers are in scope for the evaluation. Longer interviews with more variation in response are expected (like what facilitates positive recovery experiences for longer-term patients in the rehabilitation unit of a hospital).
How flexible is a semi-structured interview?
Some interviewers believe that the order and delivery of questions must be consistent across all participants. Therefore, variation is only allowed with follow-up prompts (e.g., can you tell me more about that?) and clarification questions (e.g., what do you mean by that?). This is like adding mustard to one burger and not another.
Other interviewers change the order and phrasing of questions based on context. Only the question's underlying themes and goals are consistent. This is like substituting the bun, patty, and toppings to get it right for each person.
How do you conduct a semi-structured interview?
A common misconception about the semi-structured interview is that it is a free-for-all. It takes skill and practice to understand when, how, with whom, and to what end to improvise questions and flow. Too many changes may compromise the interview's integrity by neglecting the goal, central themes, and time. On the other hand, too few changes may make the interview feel stiff, intimidating, and irrelevant to different participants.
The interviewer’s style and skill make all the difference.
Like structured interviews, we also organize semi-structured interviews around a mix of “what” and “how” questions related to key evaluation topics. Then, we ask questions that dive deeper into specific experiences to elicit illustrative examples, memories, and underlying values or beliefs.
Because the semi-structured interview can quickly become a runaway train, it is important to stay on track. Practicing ahead of time not only helps to keep questions answerable, but also accounts for time needed. Improvisations can add time. And too many follow-up prompts can result in an interview that runs out of time before all relevant questions are answered. So, we keep track of the time we have to stay on each theme before moving on and practice segues and transitions to keep the conversation moving.
Pro tip:
At the interview, we often ask questions that help us to read the room. For example, we often ask people what motivated them to talk to us. This helps us understand which questions may be more relevant for them, what the emotional tone of our conversation might be, and if there are topics to avoid. Then, we adjust questions accordingly.
What is an unstructured interview?
The unstructured interview is like a charcuterie board. It has flair instead of a frame. There is no expectation of eating anything in any order. You could eat just the cheese or no cheese at all. If you ditch the charcuterie board and rummage through the fridge for leftovers instead, we could make that work too.
Like a charcuterie board, an unstructured interview works best when the primary goal is to foster meaningful options and interactions for a select few. The conversation is organized around one or more broad themes – the fewer, the better. A list of prompts (loosely phrased questions or topic ideas) may also be prepared ahead of time. Uniquely, this interview follows the interviewee’s lead. The interviewer improvises questions to guide the discussion as it unfolds. There is no expectation that any two interviews will be the same.
When should you use an unstructured interview?
Typically, unstructured interviews occur with a small group of people and with more time. These in-depth interviews often centre on illustrative examples, memories, or stories that speak to at least one key theme. In addition, the interviewee may introduce new topics through a side tangent or spontaneous story. These interviews result in rich and complex insights into each person’s unique experience (e.g., the experience of undergoing treatment in a hospital unit as a patient).
How do you prepare for an unstructured interview?
Just as a host cannot call a single plastic-wrapped slice of American cheese a charcuterie board, an unprepared interviewer cannot call whatever they improvise an unstructured interview. Although this technique may look effortless, it requires the most effort of the three.
To prepare, we brainstorm numerous questions and prompts corresponding to each key theme central to the evaluation project. This makes it easier to recall and improvise questions if we get nervous or stuck. Then, we create a few possible options for introductory questions that do two things:
Help the interviewee feel in control of the conversation, but not on the spot. It’s a chat, not a test.
Result in a rich answer that invites natural prompts to take us forward. Specifically, we should be able to ask a gentle follow-up question that: (a) achieves clarity and specificity or (b) transitions the interviewee's train of thought to an interconnected, but still relevant, theme.
We practice these openers and prompts together to get a good feel for how they land and where we can go from there. This helps us to understand where we might fumble into a conversational dead-end so we can come prepared with the right restructuring question or transition.
Pro tip:
Spend time getting into your "interviewer character" to ensure that you bring the right energy and non-verbal prompts into the interview to help steer the conversation without becoming heavy-handed with questions. You can read more about how we do this with the post, Don’t Interview in Sandals.
How do you choose between structured, semi-structured, and unstructured interviews?
The right structure depends on three things: what you need to learn (evaluation goals), how many people you’re talking to, and how comfortable you are improvising or your skill as an interviewer.
Structure | Best for | Flexibility | What it asks of the interviewer |
Structured |
| None. Stick to the script and sit on your hands | Discipline to stick to the interview guide as written |
Semi-structured |
| Key themes or concepts are fixed, but the order, wording, and follow-up prompts can change | Active listening and confidence improvising within the evaluation scope and scheduled time |
Unstructured |
| The participant leads, and you follow and gently steer the conversation without heavy-handed questions | The most preparation, and skill at following tangents without losing the thread |
In our experience, we use semi-structured most often because the interview guide can be reviewed by clients and community advisors, and the flexibility keeps the conversation tailored and informal. In longer-term projects or when we have multiple touch-points with participants, we may opt for an unstructured interview because we have the time to get to know people, pick up conversational threads from previous interviews, and keep the experience participant-led.
The bottom line
An interview is not a sandwich, and it doesn’t have to be the same sandwich every time. The right structure depends on what you need to learn, how many people you’re talking to, and how comfortable you are improvising. Start with the goal, not the template. Then practice. Borrow a trusted colleague and time your questions or themes, notice where they stumble over unclear or clunky questions, take note of where you rush or linger, and get those transitions right so the conversation feels intuitive. Then, adjust, and practice again. You got this.
Want to keep sharpening your interviewing?
Read the rest of the series: Evaluation Interviewing, No, You’re Not Entitled to an Answer, and Don’t Interview in Sandals.
For community-serving organizations:
Not sure which structure fits your needs? Talk it through in Data Strategy Office Hours and get unstuck in an hour.
Want your team interviewing with confidence? Custom Training & Workshops builds those skills around your real context.
Take interviewing off your plate entirely so you have one less thing to worry about. Bring us in to design and run interviews as part of an Evaluation Project or one-off Light Touch Consulting task.
For fellow evaluators: pressure-test your interview design with Evaluation & Research Advising, bring us in to train your team with Custom Training, or team up on a project.
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