How to Series: In-Depth Interview Research

Guide to Conducting an IDI (In-Depth Interview Research or One-on-One Interview)

13981256424_9658f31715_zFocus groups for marketing research provide a space where you can see ideas move about between people. Information flow happens in real time and topics that aren’t top of mind benefit from the different perspectives offered. While survey research quantifies ‘how many’ and ‘how much’, qualitative methods like focus groups go deeper to shed light on ‘why’ and ‘in what way’ types of questions.

This makes them ideal for developmental purposes like new product concept-to-prototype stages, buyer understanding, positioning research and usability studies.

An IDI, also called an in-depth or one-on-one interview, consists of real-time interaction between an interviewer and a participant. It can be done in person, online or on the phone. It’s best used for situations where group interaction would be uncomfortable or misleading, where an individual’s motivations, opinions, and values are thought to exist independently of social pressures, or when the interaction between an individual and a setting, website or product is the focus.

How Many IDIs Should I Do?

The number of IDIs conducted for an individual market research study depends on the topic and the number of segments and geography. For website usability studies, I follow Nielson/Norman Groups’s recommendations of about 5 people per stage. They’ve shown this is sufficient to identify 85% of the website problems, and more testing is best done after fixing the issues found on the first round rather than loading up on numbers for one single test.

Iterative testing such as this also helps in product development or creative testing. Ideally designers can view the interviews and make adjustments in between stages.

For understanding buyers and their decision-making, I’ve done studies of 7-12 people per market or segment. Since when using interview research, the individuals are truly independent of each other, finding the same word patterns and themes arising across individuals shows that these ideas are important.

What Types of Questions Should I Ask?

It’s important to write out a series of questions prior to conducting the IDI market research and to place timings into your Interview Guide. The questions should start more broadly, giving a chance to get to know the person you are interviewing and to help them feel comfortable with the style and content of the interview. And with you.

The questions should allow for open ended responses and explanations of these answers. Where a survey might ask, ‘On a scale of 1 to 10, how likely are you to purchase a Mercedes in the next 6 months?’ an individual interview might instead start by asking about cars, their importance, and then ask, ‘How do you feel about luxury cars?’ and ‘How about Mercedes?’

7863399736_05391532c0_z How Can I Encourage the Person to Talk to Me?

Especially when videotaping an interview, the interviewer has to know how to encourage more engagement from the participant while at the same time not having every, ‘Uh-huh,’ caught on tape. Smiles, nods, or other non-verbal reassurances can all let the participant know they are doing a great job and to keep talking. Letting them know 10-15 minutes into the interview, ‘This is just what I’m looking for!’ can keep the participant going.

Some of your questions may be short, ‘Tell me more,’ ‘Why?’ or even just pausing. After all, the interview is called in-depth for a reason. In my experience, however, while a nervous participant may run on and on in an attempt to fill the silence, a happy, connected person yields a much more accurate interview. Keep in mind that we usually tell more to those we like and feel comfortable with than to those who make us feel awkward and judged or even just cold.

How Do I Interpret the Results?

While I swear by verbatim transcripts even when I am lucky enough to have an excellent note taker trailing me around, some ex-journalist types may only need their own scrawled notes. Dig into the details, whether transcripts, photos, or video, and note the things that feel significant to you. Coding these with a series of keywords will enable you to reorganize the relevant ideas.

Then as you focus on what’s most important, you will start to see patterns emerge which will point to relevant insights and recommendations.

Make sure to only include themes that have been repeated three or more times. This will give an indication that others outside of the study probably feel the same way.

Jennifer Cooper, President of BuyerSynthesis, helps established and emerging companies grow revenues through better understanding their buyers.

Photos by Heinrich-Böll-Stiftung, Raymond Zoller, and Yoshikazu Takada.

1 thought on “How to Series: In-Depth Interview Research

  1. Pingback: So You Want a Market Research Career?

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