How do you prepare for in-depth interviews?
Tips and best practices for preparing and conducting in-depth interviews.
Preparing for in-depth interviews requires more than developing an interview guide. It involves deliberate decisions about the research design, participant selection, interview setting, interviewer role, ethical safeguards, data capture, and the analytic approach used to interpret the data.
The preparation required will vary depending on the study’s purpose and methodology. A healthcare market-research IDI, for example, may require different preparation from an ethnographic interview embedded in a broader period of fieldwork. What remains consistent is the need for methodological alignment: the way participants are recruited, interviewed, recorded, analyzed, and reported should all support the research question.
This article is the second in a three-part series on in-depth interviews.
Part 1 examined the science and art of in-depth interviewing, including the methodological principles that distinguish it from a structured question-and-answer exercise.
This article focuses on what happens before and during the interview: designing the study, selecting participants, preparing the interview guide, establishing rapport, managing the interview setting, probing effectively, and addressing ethical considerations.
Part 3 turns to what happens after the interview: transcribing, coding, analyzing, interpreting, and reporting qualitative data.
Designing the in-depth interview study
Clarifying the research question
Before developing an interview guide, clarify what the study is designed to understand. A well-defined research question provides the foundation for participant selection, interview topics, probing strategy, and subsequent analysis.
The question should be focused enough to provide direction while remaining open enough to allow participants to introduce experiences or perspectives the researcher may not have anticipated.
Selecting participants
Participant selection should align with the research question and sampling strategy. In many qualitative studies, purposive sampling identifies participants who can provide relevant and sufficiently rich information about the phenomenon being investigated.
Researchers should define the characteristics that make someone relevant to the study and establish appropriate inclusion and exclusion criteria. Where meaningful comparisons are required, the sampling strategy should ensure that the relevant groups or perspectives are adequately represented within the study sample.
Recruitment should consider not only who qualifies for the study, but also whose experiences may be missing from the initial sampling frame.
Determining sample adequacy
No universal number of interviews is sufficient for every in-depth interview study. The appropriate number depends on the research question, the population’s heterogeneity, the sampling strategy, the number of groups or subgroups explored, the depth of each interview, and the analytic approach.
Where the study is designed around saturation, researchers can assess whether additional interviews continue to yield new codes, concepts, or sufficiently distinct meanings. Importantly, saturation is not a single, universally defined endpoint. Some qualitative approaches use different criteria for determining sample adequacy. For example, reflexive thematic analysis does not treat saturation as a necessary criterion, reinforcing the importance of aligning sample decisions with the chosen methodology. At the same time, a study may reach code saturation — the point at which the range of issues is largely identified — before it reaches meaning saturation, at which point those issues have been explored in sufficient depth and nuance.
Sample adequacy should therefore be treated as an iterative methodological judgment rather than a predetermined numerical target. The initial design can establish an anticipated range and recruitment plan, while ongoing engagement with the data can inform whether additional interviews are needed.
The objective is not simply to stop when “nothing new” appears. Researchers should consider whether the data are sufficiently rich and diverse to answer the research question.
Developing the interview guide
The interview guide should translate the research objectives into broad discussion areas and potential probes. It should provide structure without turning the interview into a rigid questionnaire.
Questions will often progress from easier, less sensitive topics to more complex or sensitive areas, while allowing the interviewer to follow up on relevant issues raised by the participant. The guide should also identify essential topics to cover across interviews while preserving enough flexibility for genuine exploration.
Pilot-testing the guide can help identify ambiguous wording, unnecessary repetition, sequencing problems, or questions that do not elicit the required depth of response.
Preparing for the interview
Before interviews begin, researchers need to lay the groundwork.
Accessing the research setting
Before interviews begin, researchers need to understand how they will secure access to participants and the research setting. Depending on the study, this may involve recruitment agencies, organizational gatekeepers, professional networks, community organizations, or direct participant recruitment.
Access can also involve practical, legal, cultural, or organizational considerations. Researchers should establish these requirements early so that recruitment and interviewing can proceed without compromising the research design or participant experience.
Understanding language and cultural context
Researchers should understand participants’ language and cultural context, particularly where these may influence how experiences are expressed or interpreted. The issue is not simply the words participants use, but the meanings, assumptions, norms, and experiences those words may convey.
Considering researcher presentation
How the researcher presents themselves can influence the interview relationship. Clothing, professional identity, communication style, perceived expertise, and other aspects of researcher presentation may affect how participants respond.
The objective is not to “blend in” at all costs, but to adopt a presentation appropriate to the setting that supports trust without unnecessarily emphasizing status or authority.
Researchers should also consider how their own characteristics and perceived position may shape the interaction. This is one reason reflexivity should begin before the interview rather than being treated solely as a post-interview exercise.
Preparing the interviewer
A well-designed interview guide cannot compensate for inadequate interviewer preparation. Before fieldwork begins, the interviewer should understand the research objectives, sampling criteria, interview guide, relevant terminology, ethical requirements, and the study’s boundaries.
Preparation should also include practicing the guide, anticipating likely probes, identifying potentially sensitive topics, and considering how personal assumptions or expectations might influence questioning. Where multiple interviewers are involved, calibration can help establish a shared understanding of the research objectives and interviewing principles without forcing every interviewer to conduct the conversation in exactly the same way.
The aim is not to rehearse a script. It is to ensure the interviewer is sufficiently familiar with the study to listen actively and respond thoughtfully, rather than focusing on what question comes next.
Building trust and rapport
Trust and rapport help create conditions in which participants feel comfortable sharing their experiences and perspectives. This begins before the formal questioning starts and can be influenced by factors such as communication style, cultural sensitivity, researcher presentation, and how the participant is welcomed into the interview.
Rapport does not guarantee openness or candor, but a respectful and non-judgmental interaction can reduce unnecessary barriers to meaningful discussion.
Ethical planning
Address ethical considerations during study design rather than treating them as a procedural step at the end of the preparation process. Researchers should consider potential harms, informed consent, confidentiality, data protection, participant vulnerability, and relevant cultural or contextual sensitivities.
Conducting the interview
Optimizing the interview setting
The interview setting should support privacy, concentration, psychological safety, and an uninterrupted conversation as much as reasonably possible. Depending on the study, this may mean a quiet physical location or a suitable online environment.
The choice of setting should also reflect the participant’s circumstances. Convenience for the researcher should not automatically take precedence over what enables the participant to engage comfortably and openly. Researchers should anticipate practical issues such as background noise, interruptions, connectivity issues, privacy concerns, and the presence of other people.
The objective is not to create a perfectly controlled environment, but to establish conditions that support meaningful and authentic interaction.
Establishing expectations and consent
Before the interview begins, researchers should explain the study’s purpose, the participant’s role, the expected duration, how the interview will be recorded and used, and any relevant limits to confidentiality. Participation should be voluntary, and participants should be free to decline to answer a question or stop the interview in accordance with the study’s consent process and protocol.
If recording is planned, researchers should obtain specific consent to record before recording begins. Researchers should also explain how they will store, de-identify, analyze, and report the data when these details are relevant to informed consent.
Researchers should collect only the personal information necessary for the research and consider whether participants could be identified indirectly from their accounts. Removing names is not always sufficient to achieve anonymity, particularly when participants describe distinctive roles, organizations, locations, or experiences.
Researchers should therefore distinguish between anonymization and confidentiality and make only promises they can realistically keep. When researchers use pseudonyms or other de-identification measures, they should apply them consistently throughout data management and reporting.
Interview duration
The appropriate interview duration depends on the research question, topic complexity, participant characteristics, and required depth. Many in-depth interviews last around 45–90 minutes, but shorter or longer interviews may be appropriate.
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The duration should be long enough to explore the research questions meaningfully without causing unnecessary participant fatigue. The objective is depth and relevance, not simply maximizing interview length.
Preparing to probe
The quality of an in-depth interview depends not only on the questions asked, but also on how the interviewer follows up on the participant’s responses.
Probes can clarify meaning, explore an experience in greater depth, examine contradictions, or understand the reasons behind a stated view. Useful probes include neutral prompts such as
- “Can you tell me more about that?”
- “What did that mean for you?”
- “Can you give me an example?”
- “What happened next?”
Effective probing requires listening rather than simply moving through the interview guide. The interviewer should avoid leading participants toward a preferred answer and should distinguish between exploring an issue and imposing an interpretation on it.
Recording and note-taking
Where ethically appropriate and with informed consent, audio recording provides a more complete record of the participant’s words and lets the interviewer focus on listening, probing, and maintaining the flow of the conversation rather than manually documenting every statement.
Video may provide additional information about visible behavior, such as gestures or facial expressions, but interpret such observations cautiously. Nonverbal behavior is contextual and has no single, objective meaning.
Recording does not eliminate the value of interviewer notes. Brief notes can capture contextual information, emerging analytical thoughts, or observations not evident from the recording alone. Researchers should therefore determine the appropriate balance between recording and note-taking for the study design and interview setting.
The final question
A well-designed interview guide should usually include an open-ended final question that gives participants an opportunity to raise anything they consider important but that the interviewer may not have covered.
A simple question such as “Is there anything else you think is important that we haven’t discussed?” can create space for unexpected perspectives, clarifications, or issues that didn't fit naturally into the earlier discussion.
Do not treat the final question as merely a formality. Participants may introduce information at this stage that clarifies earlier responses or identifies an issue the researcher had not anticipated. The interviewer should therefore allow sufficient time for the participant to respond rather than ending the interview immediately after the final planned question.
Closing and debriefing
Handle the end of the interview as deliberately as its opening. After the final question, the interviewer should allow the participant to add anything further, then explain what happens next, including, where appropriate, how the data will be used.
Thank participants for their time and contribution. Where the subject matter is sensitive, researchers should also consider whether any additional information, support, or follow-up is appropriate.
A brief post-interview debrief for the researcher can also be valuable. Recording immediate observations, unexpected issues, contextual information, and initial analytical reflections helps preserve insights that may not appear in the transcript alone.
From interviewing to analysis
Although this article focuses primarily on preparation and execution, preparation should anticipate what will happen to the data afterward.
Researchers should identify the analytic approach during study design because it influences how interviews are conducted, recorded, transcribed, coded, and interpreted. Different approaches — including thematic analysis, qualitative content analysis, framework analysis, grounded theory, and other methodologies — use different analytic procedures and assumptions.
Analysis is rarely a simple linear progression from coding to categorization to interpretation. Researchers typically move iteratively between the data, codes or other analytic constructs, emerging patterns, interpretations, and the research question. The specific terminology and procedures will depend on the chosen analytic approach.
For this reason, researchers should maintain a clear audit trail of key methodological and analytical decisions and remain attentive to contradictory or unexpected findings, rather than focusing only on patterns that confirm their initial expectations.
Part 3 of this series focuses on the detailed process of analyzing and interpreting interview data.
Transcribing
After each interview, researchers should record immediate reflections, observations, and emerging analytical ideas while the conversation is still fresh. These notes can provide important contextual information that may not be fully captured in the transcript.
Where transcription is required, researchers should determine in advance the level of detail appropriate to the analytic approach. Verbatim transcription aims to reproduce participants’ spoken words as accurately as possible, while more detailed approaches may also document features such as pauses, laughter, interruptions, emphasis, or overlapping speech when these are analytically relevant.
Transcription is not simply a mechanical conversion of speech into text. Decisions about what to include, how to represent speech, and how to handle unintelligible passages can influence subsequent analysis. Researchers should therefore establish transcription conventions that are appropriate to the research question and analytic method.
When researchers use automated transcription or other software, they should review the resulting transcript for accuracy, particularly where terminology, accents, multiple speakers, or technical language may cause errors.
Coding
Coding involves identifying and labeling data segments relevant to the research question or analytic focus. A code may capture an explicit statement, an underlying idea, an experience, an action, or another analytically meaningful feature of the data.
Coding is iterative. Researchers may create, combine, refine, rename, or discard codes as their understanding of the dataset develops. The specific coding process depends on the chosen analytic approach: some approaches use structured coding frameworks or codebooks, while others emphasize more flexible, reflexive engagement with the data.
The objective is not simply to label everything that participants say, but to develop an analytic representation of the data that supports meaningful interpretation.
Developing patterns and themes
Depending on the analytic approach, researchers may organize codes into broader categories, concepts, or themes. The purpose is to move beyond isolated statements and examine relationships, similarities, differences, tensions, and patterns across the dataset.
Importantly, themes should not be treated simply as topics that appear frequently. A meaningful theme captures something important about the data in relation to the research question and should be supported by sufficient evidence from the dataset.
Establishing analytic credibility
Researchers should critically examine the robustness of their interpretations rather than simply seeking evidence that confirms their initial analysis.
This may involve revisiting the original transcripts, examining contradictory, negative, or disconfirming cases, checking whether interpretations are adequately supported by the data, and considering alternative explanations. Depending on the methodology, additional practices may include peer discussion, participant feedback, triangulation, or the maintenance of an audit trail of analytical decisions.
The objective is not to prove that qualitative findings are objectively true, but to demonstrate that the interpretations are credible, transparent, and appropriately grounded in the data and research methodology.
Reporting
A strong qualitative report should allow readers to understand how the researchers moved from the research question and data collection process to the reported interpretation. Methodological decisions, participant characteristics, analytic approach, and the basis for key interpretations should therefore be described transparently.
Participant quotations can play an important role by illustrating and grounding the analysis. Quotes should be selected because they illuminate the interpretation, not simply because they are vivid or representative-sounding. Researchers should also provide sufficient context for readers to understand how the quotation relates to the analytical point being made.
The appropriate reporting format will depend on the study design, audience, and purpose. In formal qualitative research, established reporting guidance, such as Consolidated Criteria for Reporting Qualitative Research (COREQ), can help researchers assess whether they have adequately addressed key methodological and reporting details.
Reflexivity and positionality
A crucial aspect of reflexivity involves considering the power dynamics between the researcher and the participant in the interview setting, as well as how participants may perceive the researcher. Researchers should also consider how their identities, backgrounds, experiences, assumptions, positioning, and social context shape the knowledge and perspectives they bring to the interview, including their approach to questioning and analysis. Reflexivity supports ethical sensitivity by encouraging researchers to stay aware of how their engagement with participants may influence the research process.
Researchers should also consider how they may respond to uncomfortable, sensitive, or unexpected information. Preparation can include anticipating potentially difficult topics, reflecting on personal assumptions, and considering how power dynamics may influence the interaction.
During the interview, researchers should stay attentive to their own reactions without letting them signal judgment or pressure participants to change their responses. Reflexivity therefore extends beyond reflecting on the interview afterward; it involves ongoing awareness of how the researcher’s presence, assumptions, position, and behavior may shape the research encounter and subsequent interpretation.
Conclusion
Good in-depth interviewing begins well before the first question is asked. Rigorous preparation requires alignment between the research question, sampling strategy, interview guide, participant experience, interviewer role, ethical safeguards, and the intended analytic approach.
At the same time, preparation should not become rigidity. An effective interviewer enters the conversation with a clear purpose and a well-considered guide while remaining responsive to what the participant actually says. The ability to listen, probe, recognize unexpected perspectives, and reflect on the researcher’s own influence is central to generating meaningful qualitative data.
Ultimately, methodological rigor in an in-depth interview is not achieved by mechanically following a script. It comes from making thoughtful decisions before, during, and after the interview — and being able to explain the reasoning behind those decisions.
The final article in this series examines what happens after the interviews are complete:
[Part 3: Analyzing in-depth interviews: Unveiling insights from conversations.]
It focuses on the analytical process that transforms interview data into credible, meaningful, and relevant research insights.
