It all started with depth interviews. Back in the 1950s, the emerging discipline of motivational research, with its roots in psychoanalysis, used individual interviewing as its primary technique.

It wasn’t long, though, before group discussions were developed, and in the intervening period groups have come to be seen as the basic unit of qualitative research. Even now, when constant invention and reinvention mean that clients and researchers have a raft of techniques available to them, the standard refrain remains: ‘We’d like to do some groups’.

Meanwhile, the depth interview has come to be regarded as something of a poor relation: the Cinderella of the qualitative world. No one, I think, would doubt its usefulness. But its application is often restricted to a well-rehearsed set of circumstances; those clear markers in a client’s brief that automatically flip the ‘depth’ switch in the mind of the proposal-writer.

Value of depths

Discussing a sensitive subject? Use depths to avoid potential embarrassment and inhibition in the group situation. Testing individual communications or looking for detailed explanation of behaviour? Use depths to isolate the individual response. Interviewing high status respondents or professionals with particular expertise? Use depths to avoid problems of posturing, deference or confidentiality.

And, of course, depths are invaluable for overcoming the logistical problems inherent in convening certain audiences in the same place at the same time: people with physical mobility problems, geographically scattered samples, high-fliers who never leave the office before nine.

There is nothing wrong with using depths in these situations. The reasons why we have historically recommended individual interviews rather than groups still hold true. Yet what about the potential of depths outside this prescribed set of circumstances, whether to replace groups or to complement them? Why do researchers not recommend depths more often (and why don’t clients ask for them)?

Different perspective

Undoubtedly, groups do things that depths cannot, and are self-evidently preferable for certain projects. Perhaps the decision to recommend them, though, has become just too automatic. When used as part of a mixed methodology, individual interviews can add a whole different perspective, even in projects where depths would not normally be considered.

Take creative development. The received wisdom is that groups are best for researching ad campaigns, particularly those designed for ‘public’ media such as TV and outdoor. Groups encourage respondent creativity, the argument runs; they allow us to access shared socio-cultural values and beliefs.

Complementing group discussions with individual interviews in this type of research can, however, be revealing. Depths capture respondents’ immediate reactions, free from the influence of others. This can be useful for exploring the comprehension and individual appeal of concept, theme and execution.

They enable us to get to know respondents better and to talk to them on their own territory; perhaps even to observe them using the product in question. They allow us to explore the effect of creative material on a private as well as a public level. In the case of challenging advertising such as anti-smoking or drink-driving campaigns, this provides a useful counter-balance to the hostility and defensiveness that can occur in the group situation. Individual response to creative material is also likely to become increasingly important given the promised growth in personalised communications and one-to-one marketing.

Depths can also replicate better the way in which individuals encounter advertising ‘in real life’. This is particularly true in the case of interviews where respondents are recruited on the spot and interviewed for only twenty minutes or so. Such interviews also provide a means of sampling ‘virgin’ respondents: people with no experience of the research process who are unlikely to agree to attend a group discussion.

Infinite flexibility

The methodology is infinitely flexible, allowing changes to the recruitment criteria and rotation of stimulus material from one interview to the next, and affording an opportunity to test new hypotheses or follow up emerging respondent types. Some criticise it as an unholy hybrid of qual and quant; but, if used judiciously, short qualitative interviews can provide just the right balance of depth and brevity that the brief requires.

Another factor discouraging the greater use of individual interviews is the perception that their cost outweighs their value. Compared with groups, depths can seem more basic, more straightforward, more pedestrian. Groups possess an air of magic: the importance of a skilled moderator is more obvious; the process of turning transcripts into findings more mysterious.

What is more, the group methodology has been successfully ‘owned’ by the qualitative industry. Depths, by comparison, have long been the legitimate preserve of all sorts of professions: journalism and psychiatry to name but two.

No group dynamics

The role of the interviewer seems so much easier: there are no group dynamics to navigate, no dominant respondents to handle. The tendency of qual agencies to ‘try out’ their graduate trainees on depth interviews before they are let loose on groups does nothing to combat this perception.

With this in mind, is it any surprise that depth interviews tend to be devalued? As researchers, we may know that establishing the right relationship in a depth interview in order to extract the information required is no less of a skill than that of moderating eight respondents in a group. It is also a skill with which qualitative researchers are particularly well equipped; but perhaps we do not make this clear enough.

Other professions such as management consultants do, of course, have a legitimate role to play in conducting individual interviews within their own areas of expertise. Qualitative depth interviews are different, though, and we should be prepared to say so.

Increasing commoditatisation

When the perceived value of a depth interview is set against its relative cost, the difficulties are compounded. The increasing commoditisation of qual allows the easy calculation that, respondent for respondent, depth interviews are two or three times as expensive as groups.

This is not because prices are artificially inflated. On the contrary, depths are very costly in terms of the time and trouble it takes to recruit, conduct, transcribe and analyse them. When research agencies lose pitches because they have charged five pounds more per respondent than the competition, is it any surprise that they are wary of recommending depth interviews, particularly to new clients?

In short, there are genuine reasons why individual interviews are not always a viable or appropriate methodology. This is not an evangelical exhortation to recommend depths in every situation. But it is an encouragement to think again about how we use individual interviews; to consider their potential to add another dimension to a project as part of a mixed methodology; and, finally, to reclaim their value and credibility as a specialist research technique.