Surveys, interviews, and focus
groups
Lorrie Faith Cranor
September 2009
CyLab Usable Privacy and Security Laboratory
http://cups.cs.cmu.edu/
CyLab Usable Privacy and Security Laboratory
http://cups.cs.cmu.edu/
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Surveys, interviews, and focus groups
 Surveys
– Ask people set list of questions (possibly with conditional
questions or branching) with multiple choice or free response
answers
– Can be conducted in person, by postal mail, by phone, online
 Interviews
– Ask people open-ended questions, with follow-up questions
depending on their responses
– Usually conducted in person or by telephone
 Focus groups
– Group interview, usually with 5-10 participants
– Usually conducted in person
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What method should I use?

Survey
– Allows you to collect data from a lot of people relatively quickly
– Easy to collect data in standardized format, ready for analysis
– But, not very good for answering “why” questions unless you have already developed
hypothesis through other studies
– Useful for validating hypotheses from smaller studies with a larger population

Interview
– Allows you to probe mental models, what people think and why
– Semi-structured interviews allow you to explore issues as they are raised
– Allows you to clarify if people don’t understand a question

Focus group
– Many of the advantages of interviews, but more efficient as you can interview 5-10 people all
at once
– Less detail from any interviewee than you would get in an individual interview
– Not that great for testing usability because participants probably won’t all get hands on
experience with software
– Sometimes an opinionated individual can dominate a focus group
– Hard to publish papers unless focus groups are used along with other methods or you report
on a large number of focus groups together
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SURVEYS
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Designing good survey questions
 Word questions clearly, without jargon or
undefined abbreviations
 Avoid leading questions, ambiguous terms, or
emotionally-loaded terms
 Design questions to evoke truthful responses
– Non-threatening, don’t bias participants to provide
what they think you want, protect confidentiality
 Probe one dimension at a time
 Design questions such that respondents are likely
to provide a range of answers
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Multiple-choice answers
 Make sure answer choices are clear, mutually
exclusive, cover entire space of possible answers
 Make sure answer choices are at appropriate
level of granularity
 Where appropriate, allow respondents to indicate
they don’t know, don’t have an opinion, or the
question is not applicable to them
 Use consistent rating scales throughout your
survey
 Be aware that the rating scale can skew
responses (people like to think they are normal)
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More survey design tips
 Cluster similar questions together
 Do not ask respondents to perform cognitively
difficult tasks (unless you are testing their
ability to perform these tasks) such as ranking
more than 5 items
 Use a clear and attractive layout
 Pilot, pilot, pilot!
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INTERVIEWS
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Developing an interview script
 Keep your questions fairly open-ended
– You can follow-up with specific probes (“What files do you
have on your computer that you consider valuable?”
Follow up with “Do you have valuable photos? Videos?
School work? Letters?”)
 Start with general questions and get more specific so
you get their unbiased impressions before you direct
their thinking to particular details
 A semi-structured approach allows you to adjust as
needed
 Write-out all your questions and follow-up probes
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Preparing for an interview
 The day before the interview:
– Print out:
• Protocol – including detailed interview script
• Official consent form
• Payment sheet
– Prepare:
• Compensation payment
• Audio/video recording (devices, batteries, extension cords,
etc.)
• Additional material
– Send an email to the interviewee to remind him/her
of the date/time/place
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During the interview
 Explain the purpose of the study (unless you need
to hide that)
 Ask to read and sign the consent form
 If recording/video taping, turn it on!
 Perform the study!
 Debrief the person (if applicable)
 Ask to sign the signing sheet
 Give the payment
 Thank the person!
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More interview recommendations
 Schedule meetings at least one week in
advance
 Be mindful of your subject/interviewee time
 Keep a careful record of your interviews and
keep it secure!
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Analyzing interview data
 Interview can be formally analyzed through a coding process
– Transcribe interview data (yourself or with hired transcription service)
– Iteratively review transcripts and create code for concepts mentioned by
participants
– As new codes are added, check to see whether those concepts were
mentioned in previously analyzed transcripts
– Keep track of how many participants mentioned each concept to find
concepts that resonate with a lot of participants
– Group similar codes together into categories
– Note interesting quotes
 Qualitative approach
– Use concepts and categories to develop theory (Grounded theory approach,
does not start with hypotheses)
 Quantitative approach
– With large number of interviewees (~30), and questions that ask participants
to provide numerical ratings, quantitative analysis may be feasible
– Important to validate for coder reliability
 Can be used to develop mental models
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FOCUS GROUPS
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Advice on conducting focus groups
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Develop detailed script to guide you
Pre-screen participants to get a good mix of people who meet your criteria
Record everything, but don’t have cameras pointed in people’s faces so they feel
like they are under surveillance
Helpful to have at least 2 people, a moderator and a note taker
Give people name tags with their first name only
Make the session fun, informal, relaxed feel
– Provide drinks and snacks

Promote a free flowing conversation that engages all participants
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Ask open ended questions
Show people multiple things and ask them to compare
Give demos or show videos to start-off discussion
Give people handouts and ask them to circle things they like/don’t like, or jot down first
impressions before discussing with the group
Plan to do multiple focus groups to mitigate effects of dominant participant
steering conversation
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Using videos in focus groups
 Videos can provide concrete scenarios for
people to discuss
 Videos from L. Little, E. Sillence and P. Briggs.
Ubiquitous Systems and the Family: Thoughts
about the Networked Home. SOUPS 2009
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Cylab Usable Privacy and Security
Laboratory
http://cups.cs.cmu.edu/
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