The depth interview is the basic technique of qualitative research. It can be performed by the means of – among others – individual unstructured interviews, group discussions, focus groups and synectic groups.

Basically, this area of research comprises of non-directive interviews in which the respondent is encouraged to talk about the subject in more detail, rather than answer only yes or no to specific questions. Usually, the ‘funnel’ technique is used – first the broadest possible level of the issue is discussed and then the discussion is gradually narrowed down to the more concrete points.

The importance of the moderator

The investigator (usually called ‘moderator’) has a list of points which must be tackled during the interview and they gently guide the conversation towards desired subjects. It is important to not lead a formal interview but to rather follow a more friendly and unstructured discussion which helps people open up and freely express their thoughts and opinions. The moderator needs to find a middle ground between formal enquiry and a chat-with-the-neighbour kind of conversation.

The discussion leader is in most cases required to have psychological training. Depth interview’s success depends largely on the moderator’s charisma and ability to acquire as much valuable information as possible in a very limited time. At the same time the moderator needs to be sensitive to the value of remarks, which may not appear to be directly relevant to the subject but may carry interesting subconscious motivations which may be of interest to researchers.

The atmosphere created by the moderator is also a significant factor in the overall success of the interview. The moderator needs to be able to generate the most optimum atmosphere and adjust his/her behaviour to suit the type of the group involved, so that maximum cooperation is achieved.

Discussions are often recorded for the purpose of later analysis, with the full knowledge and understanding of the audience. This makes the moderator’s role even more crucial, as they need to ensure a relaxed approach and overall compliance to the interview structure. Clear anonymity usually quickly allays any suspicion and anxiety about recording and respondents open up to the honest discussion.

Demanding analysis

The analysis and interpretation of a depth interview is very demanding; it requires expert and objective attention. Researchers need to put their own opinions and perceptions into the background and not influence the outcome of the research.

Although there are many qualitative data analysis computer programs available on the market today, these are essentially aids to sorting and organising sets of qualitative data, and none are capable of the intellectual and conceptualising processes required to transform data into meaningful findings.

It should be noted that qualitative research is especially useful in developing countries, particularly in those where there is not sufficient reliable sources of data available, and where cultural practices may significantly affect patterns of consumption.


If you wish to learn more about the nature of qualitative research, read our Introduction to Qualitative Research in Medical Market or Projective Techniques in Concept Research piece. If your interests lie more on the quantitate side, please head to either Introduction to Conjoint Analysis and An Overview of Conjoint Methodologies in Medical Device Markets. Or, if you’d like to discuss your research project, please don’t hesitate to contact us here.