Popular market research techniques like surveys are fantastic for generating masses of data, and they play an incredibly important part in developing meaningful marketing strategies.

However, how do you dig down a little further to generate the kind of more intense, personal insight that can often provide a “light bulb” moment with the potential to ignite a marketing campaign?

Here at Spark, one of our favourite market research techniques that has proved time and again it has the potential to inspire a campaign, and take it in new exciting directions, is the depth or in-depth interview.

A professionally moderated interview feels like a chat between friends. The trick is in knowing when to follow the tangent and when to shut it down. We have conducted thousands of in-depths with everyone from 6-year-olds to 86-year-olds. Once people are made to feel at ease they love to talk, and we love to listen actively to generate the type of insight we are renowned for.

“Good marketers see consumers as complete human beings with all the dimensions real people have.” – Jonah Sachs


What is a Depth Interview?

The depth interview (also known as the in-depth interview) is a highly focused qualitative research technique used to conduct intensive person-to-person interviews. The aim is to focus on a specific product, situation or objective, and gain a deeper understanding of consumer behaviour.

While this all sounds very serious, at Spark we like to try and inject an element of fun into just about any market research technique we use. A relaxed interviewee is usually a more forthcoming one.

Our trained interviewers are experts at delving beneath the surface of superficial responses to uncover and assign meaning to a range of complex attitudes, behaviours and experiences. The focus is on finding out what is happening and why, rather than how many times it has happened.

depth interview in marketing research

Variations on the Depth Interview

Depth interviews fall into 3 main formats:

  1. Informal conversational: A researcher carrying our observational work in a particular setting is briefed to attempt to converse with people within that setting. With good knowledge of the general aim of the exercise but no pre-set questions, the researcher uses the conversation to spontaneously formulate open-ended questions. The participant may not necessarily be informed of the purpose of the interview which allows the interviewer the ability to explore new angles as they come up.
  2. Semi-structured: These interviews often use topic guides and pre-set questions that remain consistent throughout a series of interviews with a number or participants. The interviewer might vary the sequence of the questions and adjust the level of probing according to the way the interview progresses. The researcher is free to explore new threads and angles as they emerge during the interview.
  3. Standardised, and open-ended: With a lot of planning and preparation, a series of specific open-ended questions are prepared in advance and used consistently and in the same order throughout interviews with carefully selected participants. The purpose is to identify differences in attitude and approach between the participants. Unlike a questionnaire, the open-ended questions allow the scope of the interview to expand and draw in new ideas and attitudes.

The In-Depth Interview Advantages and Disadvantages

in depth interviews qualitative research methods

Advantage: Budget Friendly

For the budget-conscious, depth interviews may involve fewer participants and can be made to work hard. Of course, the more specific we get in terms of participant and objectives the more impact it has on budget, but we will always spend your money as if it were our own – promise.

in depth interview advantages and disadvantages

Advantage: Non-Verbal Communication

A significant part of what we communicate is non-verbal. Not 92% as you may have heard from a social experiment conducted donkeys ago, but it is very high, higher than you might expect. A face-to-face interview brings body language like gestures, voice tone, and facial expression back into focus. As a result, the interviewer gets a much fuller understanding of what it is the respondent is trying to convey. By the way, arms folded? They may be actually comfortable as opposed to “closed off” – context is key.

in depth interviews qualitative research methods

Advantage: Positive Rapport

One of the main advantages of in-depth interviews in research is that they allow the researcher to develop an informal rapport with the participant. This often means that the insight gained is richer and more varied. It allows the interviewer more scope to probe deeper into areas of particular interest and also to redirect the interview when necessary. Often, we sit down for a 60 min chat, and we end up there a lot longer – we like talking and listening to people!

in depth interviews in qualitative research

Advantage: Online? No problem

Depth interviews lend themselves to being adapted so that they can be conducted remotely. Modern online communications technology like Zoom, may not present an opportunity to inspire the same levels of trust as a personal interview, but they can still produce meaningful consumer insight. And they are very handy when conducting multi-region depths so a participant in London quickly followed by one in Leeds? Done.

interview expert

Disadvantage: Non-experts need not apply

For the depth interview to be a truly successful market research technique, the interviewer must have the right level of training, skills, and experience. It looks like it’s “just a chat” but the trust is there is a lot more taking place. Think about driving a car – it looks like “you’re just driving” but the reality is you have mastered the gears, speed, observation, radio – you make it look easy. Conducting an open-ended interview while at the same time maintaining a structure and sharp focus on the desired outcome, is a special skill.

objective results analysis

Disadvantage: Objectivity

Results are based on a small sample and are not quantifiable. Analysing them is best undertaken by independent specialists like Spark. Objectivity rather than bias is the key to analysing results, examining new ideas, and producing inspired marketing strategies. For this reason, we often conduct In-depths in a project alongside or before quantitative measurement.

Work that works

Research shouldn’t be boring. We believe that fun breeds creativity, which in turn, delivers better results. And that’s why collaboration is core to Spark projects. We work in partnership with our clients, creating the insight which turns customer understanding into strategy.