Crafting Open-Ended Questions for Qualitative Research

Open-ended questions are the primary instrument for collecting qualitative data in interviews, focus groups, and questionnaires. They invite participants to describe experiences, explain reasoning, and share perspectives in their own words. This article provides a practical framework for designing open-ended questions that produce rich, analyzable data, with attention to common pitfalls and the methodological limits of free-text responses.

Qualitative research collects non-numerical data that explores human behaviour, attitudes, beliefs, and personality characteristics that are not amendable to quantitative research. The qualitative research questions are open-ended, evolving, and non-directional, and the study design is flexible and iterative. Purposive sampling is commonly used, and the sample size is determined by theoretical saturation. Data collection is generally through in-depth interviews, focus groups, and observations. Qualitative research commonly uses thematic analysis and framework analysis, although there is no consensus on analysing qualitative data. The reporting format can be comprehensive, a summary, developmental, or selective, subject to the research question. Qualitative research's potential functions are to describe the form or nature of what exists (contextual), to examine the reasons for or associations between what exists (explanatory), to appraise the effectiveness of what exists (evaluative), and to aid the development of strategies (generative). Qualitative research can be time consuming to conduct because it explores evolving questions, difficult to generalise because it recruits limited participants, and arduous when it comes to making systematic comparisons because responses are subjective. However, qualitative research can provide depth and detail, create openness, simulate people's individual experiences, and avoid pre-judgements.

The use of qualitative research in dairy science has increased considerably in recent years, providing the opportunity to inform research and practice. Qualitative approaches in dairy science enable researchers to understand myriad topics including stakeholder relationships, decision-making, and behaviours regarding dairy cattle management, animal welfare, and disease prevention and control measures. Approaches that were used often for qualitative data collection were individual interviews and focus groups, and variations of thematic analysis were common analytical frameworks. To assess public values, attitudes, and perceptions, mixed methods questionnaires that combined quantitative data with qualitative data from open-ended questions were used regularly.

At a Glance

The table below summarises the main question types, their appropriate uses, and the data quality you can expect from each.

Understanding the Purpose of Open-Ended Questions

Open-ended questions serve a distinct function in research. They allow participants to answer on their own terms, revealing what matters to them instead of what the researcher assumes matters. A well-designed open-ended question does not lead the participant toward a particular answer, and it does not constrain the range of possible responses.

The open-ended question is a recognised instrument in qualitative inquiry. In health research, for example, open-ended questions have been used to explore the factors that help the coping of infertile women. In that study, an electronic questionnaire included structured background questions and a qualitative open-ended question related to the factors that help coping. The data was analysed using inductive content analysis, and the factors that helped coping were personal resources such as mental well-being and having good abilities to deal with the issue. A well-functioning relationship and getting help also contributed to coping, as did the ability to adapt to a childless life, which included having comforting thoughts, doing things that brought relief, and orientating thinking towards the future.

This example illustrates a core principle. The open-ended question must be broad enough to capture the participant's own priorities, yet focused enough to generate data relevant to the research question. A question that is too broad produces rambling responses that are difficult to analyse. A question that is too narrow produces short answers that miss the participant's perspective.

Core Principles for Designing Open-Ended Questions

Ask One Thing at a Time

A common error is to combine multiple questions into a single item. Consider the question, "How do you feel about the diagnosis and what did your doctor tell you about treatment options?" This asks about emotions and information recall simultaneously. The participant may answer only one part, or the response may be so diffuse that analysis becomes difficult.

Instead, separate the components. Ask about feelings first, then ask about information received. This produces cleaner data and makes analysis more straightforward.

Use Language the Participant Understands

Technical jargon, academic terms, and abstract concepts can confuse participants or make them feel inadequate. A question such as "What are your perceptions regarding the biopsychosocial model of care?" assumes the participant knows what the biopsychosocial model is. Most participants do not.

Use plain language that reflects how participants actually speak about their experiences. If you are studying farmers' decisions about disease prevention, ask about "keeping your herd healthy" instead of "biosecurity protocols." The goal is to elicit authentic responses, not to demonstrate your own vocabulary.

Avoid Leading Questions

A leading question suggests the expected answer. "How worried are you about the cost of feed?" implies the participant should be worried. A better question is, "What concerns, if any, do you have about your operation right now?" This allows the participant to identify concerns without being steered toward a particular one.

Leading questions are particularly problematic in qualitative research because they undermine the validity of the data. If you have steered the participant toward a particular answer, you cannot claim that the finding emerged from the participant's own perspective.

Allow for Silence and Thinking Time

Participants need time to formulate thoughtful responses. In interview settings, silence after a question is often productive. Resist the urge to fill the gap with additional prompts or rephrased questions. A participant who is thinking is a participant who is engaging with the question.

In written questionnaires, the equivalent is providing enough space for a considered response. A single line for a question that asks for a detailed account signals that a short answer is expected. Multiple lines or an explicit instruction such as "Please describe in as much detail as you can" signals that depth is valued.

Use Prompts to Elicit Detail

The article "Prompts, Not Questions: Four Techniques for Crafting Better Interview Protocols" suggests that prompts can be more effective than questions for eliciting detailed accounts. A prompt such as "Tell me about the day you first noticed the lameness" invites a narrative in a way that a question such as "When did you first notice the lameness?" does not.

Prompts work because they ask participants to describe events, experiences, or processes instead of to provide abstract opinions. Descriptions are grounded in concrete experience and are therefore richer and more specific than general statements.

Types of Interviews and Their Question Structures

Three types of interviews are common in social health research: structured, semi-structured, and narrative interviews. These range in format from specified sets of questions to the telling of patient stories in an organic way.

Structured Interviews

Structured interviews use a fixed set of questions asked in the same order for every participant. The questions are typically closed-ended or have limited response options. This format maximises comparability across participants but limits the depth of the data.

Structured interviews are appropriate when the research question is well defined and the range of possible responses is known in advance. They are less appropriate for exploratory research where the goal is to discover new themes or understand complex experiences.

Semi-Structured Interviews

Semi-structured interviews use a flexible protocol with open-ended questions. The interviewer follows the protocol but can probe for clarification, explore unexpected themes, and adapt the order of questions based on the participant's responses.

Semi-structured interviews are the most common format in qualitative research. They balance the comparability of a structured approach with the flexibility needed to explore complex topics. The interview guide is informed by a literature review and is pilot tested before data collection begins.

Narrative Interviews

Narrative interviews invite participants to tell their story in their own way, with minimal interruption from the interviewer. The interviewer may begin with a single broad prompt such as "Tell me about your experience with this illness" and then listen without directing the account.

Narrative interviews produce rich, detailed accounts but require skilled interviewing and careful analysis. They are appropriate when the research question concerns the meaning participants make of their experiences over time.

Question Formulation Framework

The following framework can guide the development of open-ended questions for interviews, focus groups, and questionnaires.

Step 1: Define the Research Question

Before drafting any open-ended questions, clarify what you want to learn. Write a single sentence that states the research question. For example, "What factors help farmers cope with the loss of a herd to disease?" This statement provides the anchor for all subsequent question development.

Step 2: Identify the Domains to Explore

Break the research question into domains or topics that need to be covered. For the example above, domains might include emotional responses, practical support, financial impacts, and future plans. Each domain becomes the focus of one or more open-ended questions.

Step 3: Draft Questions for Each Domain

For each domain, draft one or two open-ended questions. Use the principles described above: ask one thing at a time, use plain language, avoid leading, and allow for depth. Review each question against the research question to ensure it will generate relevant data.

Step 4: Pilot Test the Questions

Pilot testing is essential. Administer the questions to a small number of people who resemble the target participants. Ask them to think aloud as they answer, and note any questions that are confusing, ambiguous, or difficult to answer. Revise the questions based on this feedback.

The interview guide should be pilot tested before data collection begins. This step identifies problems with question wording, ordering, and length before they compromise the main data collection.

Step 5: Review and Revise

After pilot testing, review the questions again. Remove any that are redundant, leading, or unlikely to generate useful data. Check that the questions flow in a logical order and that the most sensitive topics are placed appropriately in the sequence.

Open-Ended Questions in Questionnaires

Open-ended questions are often included in surveys and questionnaires, but their use requires careful consideration. The article "Why Open-Ended Survey Questions Are Unlikely to Support Rigorous Qualitative Insights" explains why analysis of free-text responses rarely meets the bar for rigorous qualitative research. While free-text responses can enhance quantitative findings or inspire new research questions, they rarely produce data rich enough to generate robust, stand-alone insights.

This does not mean open-ended questions should be excluded from questionnaires. It means researchers should be clear about what the resulting data can and cannot support. Free-text responses can identify issues that were not anticipated in the closed questions, provide illustrative examples, and capture disconfirming cases. They should not be treated as a substitute for in-depth interviews or focus groups when the research question requires rich qualitative data.

The sequence of data collection can influence participants' responses to closed and open-ended questions. A methodological study examined whether the order of questions affects how participants respond. The findings suggest that question order matters, and researchers should consider whether open-ended questions should come before or after closed questions in a questionnaire.

Designing Qualitative Questionnaires

The article "Using Qualitative Questionnaires in Medical Education Research" offers a framework for developing rigorous qualitative questionnaires. Most students in health profession education courses are new to qualitative research, and they often assume that using open-ended questions alone constitutes a qualitative research design. This assumption reflects inexperience with qualitative ontology and a lack of methodological literature on designing qualitative questionnaires.

Qualitative questionnaires can produce rich and meaningful findings when they prioritise qualitative research values and follow a rigorous design process. The framework offered in that article guides researchers through the decision-making process and the justification for using a qualitative questionnaire.

Mixed Methods Considerations

Confusion exists among some researchers and educators regarding the classification of research designs. Some classify quantitative research studies as mixed methods research when using and analysing open-ended items on a survey. This classification is incorrect. Mixed methods research requires the integration of quantitative and qualitative data collection and analysis within a single study.

An explanatory sequential mixed-methods design might involve a structured online survey followed by semi-structured interviews with a purposive subsample of participants. The survey provides quantitative data, and the interviews provide qualitative data. Open-ended survey responses can be used to support triangulation, with integration of findings achieved through a joint display linking quantitative results with qualitative themes and illustrative data.

Common Failure Patterns in Open-Ended Questions

The Double-Barrelled Question

As noted above, asking two things at once produces muddled data. Review each question to ensure it addresses a single topic.

The Leading Question

Questions that suggest an expected answer compromise the validity of the data. Review each question for words that imply a particular response, such as "How concerned are you about..." or "What problems have you experienced with..."

The Closed Question Disguised as Open

Some questions appear open-ended but actually constrain the response. "What is your opinion about the new vaccine?" invites a single opinion, not a detailed account. A better question is, "Tell me about your experiences with the new vaccine."

The Abstract Question

Questions that are too abstract produce vague responses. "How do you feel about sustainability?" is unlikely to generate useful data. A better question is, "Tell me about a time when you made a change to your operation to reduce its environmental impact."

The Question That Assumes Knowledge

Questions that assume the participant has information they may not have produce silence or fabricated answers. "What do you think about the new regulations?" assumes the participant knows about the regulations. A better approach is to ask, "Have you heard about any recent changes to regulations that might affect your operation? What have you heard?"

The Question That Is Too Broad

Questions that are too broad produce rambling responses that are difficult to analyse. "Tell me about your farm" is unlikely to generate focused data. A better question is, "Tell me about a typical day during calving season."

Practical Implementation Steps

For Interviews

1. Develop a semi-structured interview guide with open-ended questions organised by domain.
2. Pilot test the guide with two or three people who resemble the target participants.
3. Train interviewers to probe for detail without leading the participant.
4. Record interviews and transcribe them verbatim for analysis.
5. Document any deviations from the guide and the reasons for them.

For Focus Groups

1. Develop a discussion guide with open-ended questions that encourage group interaction.
2. Limit the number of questions to allow time for discussion of each.
3. Use prompts to draw out quieter participants without putting them on the spot.
4. Record the session and note non-verbal responses that may not be captured on the audio recording.

For Questionnaires

1. Decide whether the open-ended items will support the quantitative findings or stand alone as qualitative data.
2. If the open-ended items are intended to produce qualitative data, follow the framework for qualitative questionnaire design.
3. If the open-ended items are intended to supplement quantitative findings, treat them accordingly and do not over-interpret the results.
4. Consider the sequence of closed and open-ended questions and how the order might influence responses.

Records and Measurements

Qualitative research requires careful documentation of the research process. The following records support the trustworthiness of the findings.

Interview Logs

Maintain a log of each interview with the date, duration, participant identifier, and any notable events that occurred during the interview. This log supports the audit trail and helps the researcher track the progress of data collection.

Field Notes

Write field notes after each interview or focus group. These notes capture observations that are not recorded on the audio, such as the participant's demeanour, the setting, and any interruptions. Field notes also record the researcher's initial impressions and emerging analytical ideas.

Transcription Records

Document the transcription process, including who transcribed the recordings and how the transcripts were checked for accuracy. Verbatim transcription is standard for qualitative research, but the level of detail included, such as pauses and laughter, should be consistent with the analytical approach.

Coding and Analysis Records

Document the coding process, including the development of the codebook, the application of codes to the data, and the development of themes. This documentation supports the credibility of the findings and allows others to assess the analytical process.

Sample Size and Saturation

Sample size determination for open-ended questions or qualitative interviews relies primarily on custom and finding the point where little new information is obtained, which is called thematic saturation. A refined definition of saturation is obtaining the most salient items in a set of qualitative interviews instead of attempting to obtain all the items. Salient items have higher prevalence and are more culturally important.

Research on saturation and salience examined 28 sets of interviews in which respondents were asked to list all the things they could think of in one of 18 topical domains. The domains varied greatly in size, from kinds of fruits, which are highly bounded, to things that mothers do, which are unbounded. The datasets comprised 20 to 99 interviews each, with 1,147 total interviews. When saturation was defined as the point where less than one new item per person would be expected, the median sample size for reaching saturation was 75, with a range of 15 to 194.

Thematic saturation was related to domain size and to the amount of information contributed by each respondent. Unexpectedly, saturation was reached more quickly when respondents contributed less information. In contrast, a greater amount of information per person increased the retrieval of salient items. Even small samples of 10 participants produced 95 percent of the most salient ideas with exhaustive listing, but only 53 percent of those items were captured with limited responses per person.

For most domains, item salience appeared to be a more useful concept for thinking about sample size adequacy than finding the point of thematic saturation. This finding has practical implications. Researchers should consider whether their research question requires exhaustive coverage of a domain or the identification of the most salient themes. The latter can often be achieved with a smaller sample.

Limitations of Open-Ended Questions

Open-ended questions have limitations that researchers must acknowledge.

Data Richness Depends on Participant Articulacy

Some participants are more articulate than others. A participant who is not accustomed to expressing their thoughts in writing or speech may produce thin data even with a well-designed question. Researchers should not assume that a good question guarantees a rich response.

Analysis Is Time Consuming

Qualitative analysis is labour intensive. Transcribing interviews, coding the data, and developing themes takes considerably more time than analysing quantitative survey data. Researchers should budget for this time and plan the analysis before data collection begins.

Generalisation Is Limited

Qualitative research recruits limited participants, and the findings are difficult to generalise to a larger population. The value of qualitative research lies in depth and detail, not in statistical generalisability.

Systematic Comparison Is Difficult

Responses are subjective, which makes systematic comparison across participants arduous. Researchers must develop a rigorous coding framework and apply it consistently to support credible comparisons.

Free-Text Responses Have Specific Limits

Free-text responses to survey questions rarely produce data rich enough to generate robust, stand-alone insights. They can enhance quantitative findings and inspire new research questions, but they should not be treated as a substitute for in-depth qualitative data collection.

Quality Controls and Trustworthiness

Qualitative research uses several strategies to ensure the trustworthiness of the findings. These strategies should be planned before data collection begins.

Reflexivity

Researchers should reflect on their own assumptions, values, and experiences and consider how these might influence the research. Many authors include reflexivity and positionality statements in their publications. This transparency allows readers to assess the potential influence of the researcher on the findings.

Member Checking

Member checking involves returning the findings to participants to check whether the interpretations accurately reflect their experiences. This strategy can enhance the credibility of the findings, although it is not appropriate for all studies.

Audit Trail

An audit trail documents the research process from data collection through analysis to the final report. This documentation allows others to assess the rigour of the study and supports the credibility of the findings.

Triangulation

Triangulation involves using multiple data sources, methods, or researchers to cross-check the findings. In a mixed methods study, open-ended survey responses can be used to support triangulation, with integration of findings achieved through a joint display linking quantitative results with qualitative themes.

Professional Escalation Criteria

Researchers should recognise when their open-ended questions are not working and take corrective action.

Escalate When Participants Cannot Answer

If participants consistently struggle to answer a question, the question is probably flawed. Revise the question or remove it from the protocol. Do not persist with a question that is confusing participants.

Escalate When Responses Are Thin

If responses are consistently short and superficial, the question may be too narrow or too abstract. Consider whether the question needs to be broadened or reframed as a prompt.

Escalate When Data Do Not Address the Research Question

If the data collected do not address the research question, the questions are not aligned with the research aims. Return to the research question and revise the interview guide or questionnaire accordingly.

Escalate When Analysis Reveals Inconsistencies

If the analysis reveals inconsistencies in how different interviewers asked the questions or how different participants interpreted them, additional interviewer training or question revision may be needed.

Welfare and Safety Context

Qualitative research often explores sensitive topics. Researchers have a responsibility to protect participants from harm.

Informed Consent

Participants must understand what the research involves and give their consent freely. The consent process should explain how the data will be used, who will have access to it, and how confidentiality will be protected.

Confidentiality

Researchers must protect the identity of participants. This includes removing identifying information from transcripts and reports and storing data securely.

Emotional Distress

Open-ended questions can elicit distressing memories or emotions. Researchers should be prepared to respond appropriately, including referring participants to support services if needed.

Researcher Well-Being

Researchers who conduct interviews on sensitive topics may experience emotional distress themselves. Institutions should provide support for researchers as well as participants.

Frequently Asked Questions

What is the difference between an open-ended question and a closed question?

A closed question offers a limited set of response options, such as yes or no, or a rating scale. An open-ended question invites the participant to respond in their own words without predetermined options. Open-ended questions are used in qualitative research to explore experiences, beliefs, and reasoning in depth.

How many open-ended questions should I include in an interview?

There is no fixed number. The number depends on the research question, the depth of exploration needed, and the time available. A semi-structured interview might include 5 to 10 main open-ended questions with probes, while a focus group might cover 3 to 5 questions in a session. Pilot testing will help you determine whether the number of questions is manageable.

Can I use open-ended questions in a survey?

Yes, but you should be clear about what the resulting data can support. Free-text responses to survey questions can enhance quantitative findings and inspire new research questions, but they rarely produce data rich enough to generate robust, stand-alone qualitative insights. If your research question requires rich qualitative data, consider in-depth interviews or focus groups instead.

What is the difference between a structured, semi-structured, and narrative interview?

A structured interview uses a fixed set of questions asked in the same order for every participant. A semi-structured interview uses a flexible protocol with open-ended questions that the interviewer can adapt based on the participant's responses. A narrative interview invites the participant to tell their story in their own way with minimal interruption.

How do I know when I have interviewed enough people?

Sample size in qualitative research is determined by thematic saturation, which is the point where little new information is obtained. A refined definition of saturation is obtaining the most salient items in a set of interviews instead of attempting to obtain all items. Research suggests that even small samples can produce most of the most salient ideas, but the required sample size depends on the domain size and the amount of information contributed by each respondent.

What should I do if participants give very short answers?

Short answers may indicate that the question is too narrow, too abstract, or confusing. In an interview, you can probe for more detail with prompts such as "Can you tell me more about that?" or "What happened next?" In a questionnaire, you may need to revise the question or provide more space for the response.

How do I avoid leading questions?

Review each question for words that imply an expected answer. Questions that begin with "How concerned are you about..." or "What problems have you experienced with..." suggest that concern or problems are expected. A neutral question such as "What has your experience been with..." allows the participant to identify what matters to them.

What is the difference between a qualitative questionnaire and a survey with open-ended questions?

A qualitative questionnaire is designed according to qualitative research values and follows a rigorous design process. It prioritises depth and participant perspective. A survey with open-ended questions typically combines quantitative items with a few free-text items, and the free-text responses are used to supplement the quantitative findings instead of to stand alone as qualitative data.

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References and Further Reading

• Research Data Framework. National Institute of Standards and Technology.
• EQUATOR Network. EQUATOR Network.
• Experimental Design Assistant. NC3Rs.
• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.
• A qualitative study of the factors that help the coping of infertile women.. Nursing open, 2022.
• Open-ended interview questions and saturation.. PloS one, 2018.
• Why Open-Ended Survey Questions Are Unlikely to Support Rigorous Qualitative Insights.. Academic medicine : journal of the Association of American Medical Colleges, 2018.
• The open-ended question.. Journal of nutrition education and behavior, 2011.
• Mixed Methods or Mixed Up?. Journal of dental hygiene : JDH, 2023.
• Invited review: Qualitative research in dairy science-A narrative review.. Journal of dairy science, 2023.
• A Concise Review on Qualitative Research in Dentistry.. International journal of environmental research and public health, 2021.
• Using Qualitative Questionnaires in Medical Education Research.. Perspectives on medical education, 2024.
• How do mothers with advanced cancer experience anxiety about present and future of their children aged 6-12 years: a phenomenological interview study.. 2026.
• Face-to-face or screen-to-screen: gynecologic oncology fellowship interview applicant perspectives on interview format. 2026.
• Contextualizing Evaluation in Research Consortia: A Reflective Case Study from the Research Centers in Minority Institutions (RCMIs) Program. 2026.
• Supporting entrepreneurial resilience: An experimental study protocol.. 2026.
• Preparing tomorrow's physicians for AI-driven healthcare: insights from a study on medical students', interns', and residents' knowledge, attitudes, and educational needs.. 2026.
• Caregivers' experiences of caring for children with developmental dysplasia of the hip: a qualitative descriptive review.. 2026.
• Use of the Dynamic Systems Development Method to Inform Technology-Assisted Motivational Interviewing (TAMI) for Tobacco Cessation: Qualitative Study.. 2026.
• Challenges and recommendations for collecting and quantifying implementation costs in practice: a qualitative interview study. Implementation Science Communications, 2024.
• Prompts, Not Questions: Four Techniques for Crafting Better Interview Protocols. Qualitative Sociology, 2021.
• Approaches to qualitative research in mathematics education : examples of methodology and methods. 2015.
• Three types of interviews: Qualitative research methods in social health. Journal of social health and diabetes, 2013.
• Learning Purposive Communication: A Personal Narrative Experience of Non-Teacher Education Students. International Journal of Multidisciplinary Applied Business and Education Research, 2023.
• Does the sequence of data collection influence participants' responses to closed and open-ended questions? A methodological study. International Journal of Nursing Studies, 2012.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.