In-Depth Interviews (IDIs) in Market Research [2024 Guide]

Wish you could have a detailed conversation with key customers or target prospects to gather feedback about your brand, products, or services?

In-depth interviews (IDIs) are an excellent type of market research to accomplish this goal as they are often used to gather detailed and comprehensive information from individuals or small groups. 

In this guide, our market research company explores the advantages and disadvantages of using in-depth interviews in market research, how they differ from phone surveys, and the steps involved in conducting them. 

Article Contents

Whether you're a marketing professional or simply interested in the research process, this ultimate guide will provide you with valuable insights into this powerful research method. Let's get started.

In-Depth Interviews (IDIs): Definition 

First and foremost, what are in-depth interviews in marketing research?

In-depth interviews, or IDIs for short, are a qualitative research method used in marketing research to gather detailed and comprehensive information from individuals or small groups. 

They involve one-on-one conversations between a trained research interviewer and the participant, with the aim of exploring the person’s thoughts, attitudes, and experiences related to a specific topic or product.

In-depth interviews are typically conducted in a structured or semi-structured format, where the researcher has a predetermined set of questions to ask the participant, but is also open to exploring new topics that arise during the interview. 

Importance of Conducting In-Depth Interviews

The importance of in-depth interviews in market research is that they allow organizations to gather rich and detailed feedback from participants.

Feedback that can be used to gain insights into their behavior and decision-making processes. 

They are particularly useful when exploring complex topics, as they allow participants to explain their perspectives in depth, and to elaborate on their reasoning.

What are the Benefits of In-Depth Interviews in Market Research?

In-depth interviews are a powerful research method that can provide valuable insights into your target audience's perceptions, buying behaviors, preferences, and other valuable KPIs. 

While they are more time-consuming and expensive to conduct, the detailed data and personal connection with participants make them a valuable tool in market research.

More specifically, here are the benefits of conducting market research interviews:

1. Detailed insights

In-depth interviews provide researchers with the opportunity to delve deep into the participant's thoughts, attitudes, and experiences related to a specific product or topic.

This results in a more detailed and nuanced understanding of the participant's perspective than other research methods such as online surveys.

2. Flexibility in conversation

Being that they are more conversational in nature, IDIs are flexible and adaptable to the participant's responses.

The interviewer can probe further, ask follow-up questions, and explore new topics that arise during the interview, leading to a more natural and productive conversation.

3. Personal connection

In-depth interviews are conducted on a one-on-one basis, which allows the interviewer to establish a personal connection with the participant.

This rapport can result in more candid and honest responses because the participant is more comfortable in sharing their feedback.

4. More in-depth insights 

As the name alludes, IDIs result in rich and detailed data that can be analyzed in depth to gain insights into the participant's behavior and decision-making processes.

This information can be used to inform marketing strategies, product development, business decisions, or other objectives for conducting market research.

What are the Disadvantages of IDIs?

Careful consideration of the pros and cons of in-depth interviews can help ensure that the research results are valid, reliable, and actionable. 

So, while in-depth interviews are a powerful research method, they also have a few disadvantages that should be taken into account when planning a research project. 

The best way to understand what type of methodology is best for your unique goals, timeline, and budget is to consult a market research company like Drive Research.

In the meantime, here are a few disadvantages of in-depth interviews that can cause organizations to choose an alternative methodology:

1. Time-consuming

IDIs require a significant investment of time, both in terms of conducting the interviews themselves and in analyzing the data afterward.

This can be particularly challenging when working with a large sample size. In most cases, interviews last anywhere from 15 minutes to an hour. That can add up to speaking with 25+ participants.

2. Expensive

Compared to other research methods, such as online surveys or phone interviews, in-depth interviews can be more expensive to conduct.

This is largely because of the time commitment. It takes more project management time to create an interview guide, recruit participants, conduct the interviews, and analyze the feedback.

Recommended Reading: What is the Most Cost-Effective Market Research Methodology?

3. Small sample size

In-depth interviews typically involve small sample sizes, which means that the findings may not be representative of the larger population. This can limit the generalizability of the results.

How Do You Conduct a Market Research Interview?

In-depth interviews can be conducted by phone, by video conference, or in person.

Oftentimes this research methodology uses a third-party research company to lead a conversation. Here's an inside look at the in-depth interview process with our market research company, Drive Research.

Step #1: Kickoff Meeting

It all starts with the kickoff meeting. Here is where market research pros will walk clients through the finer details of the project.

This includes reviewing the objectives, timeline, interview criteria, honorariums, and more.

In this blog post, we cover what goes into market research kickoff meetings

Step #2: Recruiting for interviews in market research 

The qualitative recruiting process is when the market research team will start seeking interview candidates.

Depending on how specific the interview criteria are, this process could last a week or less, or several weeks.

Safe to say recruiting general consumers within a target market is faster than CEOs that work for Fortune 500 companies.

Learn more about our detailed qualitative recruiting process.

qualitative recruiting process by drive research

Step #3: Fieldwork

The fieldwork stage is when the actual in-depth interviews take place. Qualified market research interviewers like to think of themselves as gold miners who try to find pieces of information to help clients drive future strategies.

Learn more about what makes a great research interviewer.

Step #4: Reporting

In this step, the market research team takes the findings from all of the interviews and presents them in an IDI market research report.

Audio files can also be included in the report package so clients can go back and listen to interviews if needed.

Step #5: Debrief 

After the report has been delivered, the market research team will review the findings from the in-depth interviews.

The discussion will cover the background and methodology of the study briefly and then focus on the key findings from the research.

Cost of IDIs in Market Research

The cost of conducting IDIs in market research can range from a few hundred to several thousand dollars per interview, depending on several different factors.

Collecting quotes from market research firms or consultants can give you a better idea of the specific costs involved in your project.

To provide more context, below are the factors our market research company considers when determining the cost of IDIs for our clients.

  • Number of interviews: The more interviews you conduct, the higher the cost will be. IDIs are often conducted with a smaller sample size compared to surveys, but costs can still accumulate, especially if you're targeting a niche or hard-to-reach demographic.

  • Length and complexity of interviews: Longer and more complex interviews typically require more resources and expertise to conduct, which can increase costs.

  • Recruitment and incentives: Recruiting participants for IDIs can be time-consuming and may require the use of specialized recruitment firms or platforms. Additionally, participants may need to be incentivized to participate, which adds to the overall cost.

  • Location: Conducting IDIs in certain locations or regions may be more expensive due to factors such as travel costs or higher local market research rates.

  • Analysis and reporting: After the interviews are conducted, there will likely be costs associated with transcribing, coding, analyzing, and reporting the data.

When to Choose In-Depth Interviews Over Phone Surveys

So, why choose in-depth interviews? And why choose them over phone surveys?

As a market research company, we know choosing a research methodology can be tough if you are new to research or unsure about the benefits of different research methodologies.

The decision on what methodology to use in a market research study is often based on three factors.

  1. What are your objectives? Quantitative research methodologies like surveys are best for measuring while qualitative research methodologies like IDIs are best for exploring. 

  2. What is your timeline? Typically, it's safe to say an online survey project can be completed faster than in-depth interviews.

  3. What is your budget? The cost of market research varies, but in most instances, an online survey will be cheaper than in-depth interviews.

If your objectives, timeline, and budget align with conducting qualitative research, the next question you may have is: “What’s the difference between IDIs and phone surveys?”

Compared to phone surveys, the guide for an in-depth interview is looser and interviewers are trained to dig deeper throughout the conversation. It is a two-way communication where an interviewer can probe for more detailed responses.

Whereas phone surveys, take a few minutes to complete, ask mainly close-ended questions, and limit follow-up questions. They are much more rigid than in-depth interviews in that phone surveys don't allow too much wiggle room to ask follow-up questions throughout the study.

Other Frequently Asked Questions About In-Depth Interviews

Below are some commonly asked questions our market research company hears from organizations interested in conducting in-depth interviews.

However, it's important to note that the specific questions asked may vary depending on the research objectives, target audience, and industry context.

How long do IDIs take?

The length of these interviews in market research often depends on the objectives of the project

For example, if an organization wanted to get insight into customers' user experience (UX) on its website, the IDIs may be completed through online screen-sharing software and could take upwards of 45 minutes.

However, a conversation about an organization merger and a rebrand could take anywhere from 20 to 30 minutes.

The budget available can also play a role in the length of an in-depth interview. For example, a 90-minute interview will likely require a higher incentive for people to participate. It could also take longer to find people who can find the time to join a discussion that long.

All of these types of factors play a role in higher market research costs.

How many in-depth interviews are needed?

Of course, it always depends on the objectives of the study, but firms usually recommend anywhere from 8 to 14 market research interviews depending on how difficult the audience is to reach.

After roughly 8 interviews, our team often hears repeat information and common themes in the interviews.

What are some best practices for conducting successful in-depth interviews?

Conducting successful in-depth interviews requires careful planning and implementation.

To earn quality feedback, here are some best practices to consider:

  • Clearly define research objectives: Begin by defining the specific goals and objectives of your research with project stakeholders. Clearly articulate what you aim to learn or understand through the in-depth interviews.

  • Develop an interview guide: Prepare a structured interview guide that includes a list of topics or questions to be covered during the interview. This helps ensure consistency across interviews and allows for comparability of responses.

  • Build rapport with participants: Establish a comfortable and respectful atmosphere to build rapport with participants. Create a positive and non-judgmental environment that encourages open and honest responses.

  • Active listening and probing: Practice active listening during the interviews. Encourage participants to elaborate on their answers by asking follow-up or probing questions. This helps to delve deeper into their experiences, thoughts, and opinions.

  • Record and transcribe interviews: Use appropriate recording equipment and obtain consent from participants to record the interviews. Transcribe the interviews accurately for later analysis, ensuring confidentiality and anonymity.

Final Thoughts

In-depth interviews in market research offer a unique and valuable perspective on consumer behavior, motivations, and perceptions.

By delving deep into individual experiences and opinions, IDIs provide rich and nuanced insights that quantitative methods may not capture.

This ultimate guide has equipped you with a comprehensive understanding of IDIs in market research, from their definition and importance to the benefits and limitations they bring.

Contact Drive Research to Conduct IDIs

Drive Research is a full-service market research company specializing in in-depth interviews. We work with brands from across the country to execute IDIs whether it be in person, via phone, or through video conferencing.

Our market research firm offers related services to offer end-to-project management such as finding and scheduling participants, interview design guides, interviewing, reporting, and more.

Contact Drive Research by filling out the form below or emailing [email protected].

emily taylor about the author

Emily Taylor

As a Research Manager, Emily is approaching a decade of experience in the market research industry and loves to challenge the status quo. She is a certified VoC professional with a passion for storytelling.

Learn more about Emily, here.

subscribe to our blog


Market Research Glossary Other Market Research Services