Method · IDI

In-depth interviews

For hard-to-gather profiles and subjects nobody discusses in a group.

A highly specific qualitative technique: it gathers information from tightly defined profiles who usually have packed schedules — executives, medical specialists, industrial buyers, opinion leaders. A guided but not rigid hour-long conversation reaches a level of detail no questionnaire achieves.

How it works

The profile is defined and recruitment is one by one, with a verified screener.

A topic guide is designed, not a closed questionnaire.

The interview is conducted in person or remotely, recorded and transcribed.

Analysis looks for patterns across interviews, not isolated anecdotes.

When to use it

Cases where it fits

When the profile is so specific that assembling a group is unfeasible.
When the subject is sensitive and the presence of others inhibits the answer.
In B2B markets, where the buyer is one specific figure.
As an exploratory phase before designing a quantitative questionnaire.

At a glance

Typical sample: 8 to 30 interviews depending on the number of profiles
Duration: 3 to 6 weeks, recruitment included
Coverage: In person or remote

What you get

Full transcripts
Analysis report with supporting verbatims
Map of recurring themes and tensions
Hypotheses for the quantitative phase, if there is one

Frequently asked questions

How many interviews are enough?

As many as it takes until no new themes appear — what qualitative research calls saturation. In practice that is usually eight to twelve per well-defined profile; with several profiles, the number multiplies per profile, not across the total.

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