In-depth interviews (IDIs), in which a moderator interviews a single respondent, can be essential for exploring sensitive topics or accessing hard-to-reach demographic data, whether face-to-face, online or by telephone.

IDIs can be employed in addition to or in conjunction with focus groups when more specific and detailed information is required from each respondent or when differences of opinions need to be explored in a variety of respondents.

Respondents tend to feel more at ease and thus are more talkative in a one-on-one setting especially when discussing topics of a more sensitive and personal nature. This also allows for follow-up questions that were not initially included in the discussion guide.

IDIs can be recorded and translated in real time. These recordings can therefore be analyzed and key information extracted to then be made into detailed reports.

Online and telephone interviews are generally the most cost-effective and facilitate the obtaining of information from participants living in different locations, but complex or sensitive issues can be explored more easily face-to-face.