Interviews and focus groups

Interviews trade scale for depth, and structure decides the trade

Intuition

A survey tells you what many people ticked. An interview tells you why one person did, and lets you ask the next question. The more you script it, the easier the answers are to compare and the harder it is to follow a surprise.

An interview is a guided conversation in which one person seeks information from another. It is used in initial exploration, requirements gathering, and evaluation and subjective reactions. It is not appropriate for information from a large sample and takes significant time and resources.

Compare

Unstructured and semi-structured

Unstructured: a list of topics as a guide. Start with an initial question and let the interviewee choose. If the conversation stalls, introduce another topic.

Semi-structured: start with a set of questions, maybe like a fully structured interview, with more room for clarification and probing.

Use for deep digging, an unfamiliar domain or users. Participants educate you and help you write questions for a later structured interview.

Fully structured

A rigid script presenting questions in a well-defined order. Easy to analyse, difficult to follow up an unanticipated answer.

Use when you want to compare responses across individuals, for example to understand responses to designs or systems.

Exam detail

Sample exam question 19 on fully structured interviews. Correct: all participants get the same questions in the same order, and responses are easier to compare and analyse. Wrong: flexibility to explore new topics, adapting questions, and “best suited for exploratory research”.

Digital conferencing tools (Skype, Zoom and similar) offer other forms: participants are in their own environment, there is no travel, and for sensitive issues participants can be anonymous.

Plan, word and run the interview with care

Mechanism

Plan: 1 identify the objectives, 2 select the type, 3 decide how you will analyse the data, 4 write the questions, 5 test them, 6 determine the players, 7 prepare the materials.

Questions: if you have many, split into several sessions, and do not run beyond two hours without a break. Word them so they are clear, understandable and impartial. Keep them short because long multi-part questions are hard to remember. Avoid double-barrelled questions (more than one issue at a time) and double negatives.

Run: introduction (introduce yourself, explain the goals, reassure about ethics, ask to record, present the consent form, capture demographics), warm-up (an easy, non-threatening first question), main body (logical order, most important questions), cool-off (a few easy questions to defuse tension), closure (thank the interviewee and signal the end, for example switch the recorder off).

Interviewer behaviour matters. Do not pre-empt an answer (“You seemed to like this use of colour…”). Body language such as smiling or looking disapproving strongly influences agreement, and participants may agree with whatever they think the interviewer wants. Prestige response bias is the participant trying to agree with certain statements. Disadvantages of interviews: potential unbounded discussion, high effort and skill, a large amount of data and problems of recall. Advantages: deep data, open-ended and exploratory.

Focus groups interview people together

A focus group interviews people in groups: a representative sample of the target population, normally three to ten people led by a trained facilitator. For a university website evaluation the slide gives two designs: one diverse group (2 administrators, 3 faculty and 3 students) or three homogeneous groups (administrators, faculty, students). The facilitator guides and prompts discussion, encourages quiet people and stops verbose ones dominating.

Focus groups suit shared issues rather than individual experiences. They have a pre-set agenda with flexibility to follow unanticipated issues.

Compare

Advantages

• Allows diverse or sensitive issues to be raised
• Multiple points within a collaborative process
• Good at gaining a consensus view
• Increases interactivity between participants

Disadvantages

• Inappropriate for controversial topics
• Depends highly on the people in the group
• High effort: skill and resources

Pitfall

Note the near-contradiction in the lecture. Focus groups allow sensitive issues to be raised yet are inappropriate for controversial topics. Answer “sensitive and diverse” as an advantage and “controversial” as a disadvantage, exactly as listed.

Recall

Which interview structure would you pick to compare responses across people, and why?

Fully structured. The same questions in the same order make responses easy to compare and analyse.