1. Chapter 15: Working with human subjects

2. Working with human subjects
Finding them – who, how many?
Treating them right
Other concerns
Deceptive research, longitudinal studies, children,
Populations with specific concerns, International concerns
Regulatory changes
Public trust

3. Identifying potential participants
Find participants who meet your goals
Mismatch
Tool is for professionals –
should you use students as your participants?
Unrepresentative samples?
Tools for broad ranges of age, socio-economic status, and education but
.. Undergraduates as study participants

4. Factors to consider User goals Background Motivation Expertise Gender
Age
Not all factors are always important, but..
.. Should always be considered

5. How many participants? More is better, right?
Increased statistical power helps find subtle effects, but
Large studies are expensive

6. Controlled experiments and empirical studies
Need enough participants to produce statistically significant results
Depends on design
Between-subjects -> more participants
See Chapter 4 for more detailed discussion
Use statistical methods to determine how many
Sample size calculations, based on effect size, variance in performance, and desired statistical power
Usually, try for 20 or more.

7. Fewer participants for
Case studies
Ethnographies
Usability studies
5 users for heuristic evaluation? (Nielsen ,1994)
Hotly debated - some claim 10 +/-2 (Hwang & Salvendy 2010)
Others say more (Schmettow, 2012)

8. Other factors Difficulty of finding participants
Some can be hard to find
Experts
Users with disabilities – see chapter 16
Time – can’t do large subjects if each one takes too long
Need more participants for pilot studies
Consider pragmatic issues in study design

9. Recruiting participants
Experiments, usability studies
Advertisements, community groups, professional organizations
lists, online groups, social networks
Ethnographies & long-term case studies
Build relationships
Incentives: cash, pizza, etc..
Build a database for future consideration
With consent

10. Care and handling
Research studies should be designed to protect participants
Informed consent:
Research participants must be provided with the information needed to make an informed consent as to whether or not they will participants

11. Risks Some scientific research can have substantial risk
Drug trials, medical devices
Famous medical and psychological experiments led to current models
Most HCI experiments are low risk
Fatigue? Eye or muscle strain?
Social media, mobile, ubiquitous studies – novel privacy risks

12. Protecting participants
Respect for persons
Allow individuals to make independent and autonomous decisions
Provide necessary information
Beneficence
minimize possible harm
maximize potential benefits
Justice
Neither burden nor benefits should limited to certain populations.
Codified in US by the “Common Rule”

13. Privacy protection
Obtain consent for the collection and storage of personally identifying information (PII)
Limit information collected – only what is necessary
Identify uses of information
Limit use, disclosure, and retention
Securely protect information
Disclose policies and procedures
Provide means of addressing concerns
Be accountable.
Be careful with photography, audio, and video recording

14. Privacy protection example
Study of electronic medical records (see Chapter 13)
Record audio, video, screen capture during clinic visits
Very identifiable
In US, privacy laws apply
Potentially sensitive details
Study can still be done, but..
Be careful with idea
Protect data carefully – store securely and limit access

15. Informed consent Informed: Participants should understand
Reason for conducting study
Procedures involved
Potential Risks
How they can get more information
Present this information clearly, accessibly, and without jargon

16. Informed consent Consent - Participation should be
Voluntary
Free from any implied or implicit coercion
Decision not to participate should not lead to repercussions or retaliation
Withholding of medication
Disapproval of researcher
Punishment by employer

17. Participant rights Participation is voluntary
Participants can choose to stop participating at any time, without penalty
Consent can be withdrawn at any time
Participants have the right to be informed of any new information that will affect their participation in the study

18. Informed consent disclosure
Title and Purpose of study
Description of Procedures
Duration
Risks
Benefits
Alternatives to Participation
Confidentiality
Costs/Additional Expenses
Participant’s Rights
Contact Information
Supplemental Information

19. Procedures Participants read disclosure (or have it read to them)
Discuss and answer questions
Participant (or representative) signs statement

20. Participant statement
Participant states that they
Have volunteered to participate
Have been informed about tasks and procedures
Have had a chance to ask questions and had questions answered
Are aware that they can withdraw at any time
Consented prior to participation in the study
Provide copy (with contact information) to participants.

21. Writing informed consent forms
Write clearly and carefully
Pilot test
Consent must be given by an individual who is capable of understanding
Parents, guardians
Be aware of local or national regulations or laws

22. IRBs: Institutional Review Boards
Committees that examine human subjects research for appropriateness
Different names outside of the US
Protect
Participants
Researchers
Institutions
You may need to educate IRBs about how HCI research is done
Don’t conduct studies without appropriate review

23. Changes to US Regulations
Common Rule – 1991
2011 – Preliminary version of proposed changes
Final version
changes may take effect
Consult your IRB – ensure that your understanding of regulations and requirements is up-to-date

24. Respecting participants: Study Design
Beware of blurred lines
Facebook study of adjusted content in news feeds
Reductions in positive posts on a user’s news feed associated with reductions in positive content in user’s post (and vice- versa for negative content) (Guillory et al. 2014)
Study was consistent with Facebook terms of service..
.. So no consent
.. But still generated lots of concern
Research on commercial platforms can be in a “gray area”
What is legal vs. what is considerate

25. Respecting participants: practical issues
Compensate when possible
Provide comfortable surroundings
Allow for flexibility in scheduling
Try not to bias participants
“Don’t you love the new tool that I built?”
Try not to give feedback on task performance
Aim for “comparative studies
participants don’t know which tool you developed.

26. Deceptive Research
What if informing subjects about your study may bias them?
Online banking: do people pay attention to security images? (Shechter, et al., 2007)
If you tell participants what you’re looking at, they’ll be sensitized, and results will be biased
Instead, use deceit – tell them that your study is intended to “help make online banking better”
Use this technique carefully and sparingly
Harder to get IRB approval
Debrief afterwards

27. Longitudinal (“multiwave”) studies
Multiple sessions
Study learnability
Long-term field studies
Challenges: drop-outs, non-response, technological difficulties
Design accordingly
Automate data collection
Structure incentives to encourage retention
Increase numbers
Simplify studies

28. Working with children Parents consent
Children assent - agree to participate
Allow parents to observe
But not interfere..
At least for younger children
Appropriate rewards and task structure
Meet children’s cognitive capacities

29. Populations with specific concerns
Age, ethnicity, health…
Challenges in recruiting, scheduling, retaining
Simplify designs
Understand context and concerns of potential participants..

30. International concerns
RMHCI is US biased
Terminology and laws may differ outside of US
Understand local regulations
.. But also expectations and cultural norms
For collaborative/expatriate studies, human subjects review at both “home” insitution and locally

31. Online research Well-suited for web applications or online tools
Recruiting
Access to broader pool of participants
Anonymity may make demographics and skills hard to verify
Surveys, usability evaluations, ethnographies have all been done online

32. Ethical concerns
Studies of online communities – what is the expectation of privacy?
Informed consent and debriefing are tricky

33. Closing thoughts Participants are crucial – treat them well
Allow plenty of time
Food and drink
Breaks as needed
Make participation fun!