Focus groups yield less individual depth per unit time than interviews
Aliases: depth trade-off · shared airtime · individual narrative
What it is
For a fixed session duration, focus groups usually trade individual narrative depth for breadth of perspectives and participant interaction. People share turns, so a moderator cannot continuously probe each person's timeline, exceptions, and reasoning. Meeting more people in one hour is therefore not equivalent to collecting the same number of individual interviews.
Why it happens
Every clarification and probe consumes group time, while sensitive experiences and complex work processes require sustained attention and trust. Switching among speakers shortens individual narrative chains and lets common topics crowd out low-frequency detail. Interaction can also cue memories, juxtapose experiences, and make public norms negotiable, producing evidence that an interview may not elicit naturally.
Studying it
Method comparisons should hold the research aim constant and record total researcher labor, airtime per participant, complete incident narratives, depth of probing, viewpoint diversity, and peer-elicited material. Theme counts favor groups and individual word counts favor interviews. The relevant quality criterion is whether the material supports the intended inference and decision.
Where it stops holding
Lower depth is a common resource trade-off, not a universal ordering. Interaction may produce decisive evidence efficiently for shared language, group norms, or coordinated work. Interviews are usually better for trauma, power conflict, detailed timelines, and confidential information. Groups are not automatically cheaper once recruitment, scheduling, facilitation, and analysis of interaction are included.
Applying it
- Prefer interviews for personal journeys, sensitive disclosure, and continuous causal accounts.
- Choose groups when the interaction among vocabulary, norms, and disagreement is the object of interest.
- In a mixed sequence, use groups to expose axes of dispute and interviews to trace individual cases, or reverse the order to examine public negotiation.
- Pilot one session, then adjust group size and guide using usable airtime, traceable narratives, and analysis effort.