What is the primary characteristic of an interview in research?

The primary characteristic of an interview in research is indeed a one-on-one conversation between the researcher and the subject. This format allows for a deeper exploration of individual perspectives, experiences, and emotions. Unlike other methods such as group discussions or surveys, an interview is personalized, enabling the researcher to ask follow-up questions, clarify responses, and adapt the conversation based on the subject's answers. This interaction facilitates a more nuanced understanding of the data collected, capturing the subtleties of personal narratives and insights that might not emerge in more structured or group-based formats.

In contrast, group discussions involve multiple participants and are more focused on collective perspectives rather than individual depth. Questionnaires limit responses to predetermined options, thus reducing the flexibility and richness of the data. Public forums are characterized by a lack of confidentiality and can limit the depth of responses due to audience dynamics. Therefore, the one-on-one nature of interviews is what distinctly marks them as a vital method in qualitative research.