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508 CHAPTER 16 Working with research participants with disabilities

doubters who will look at data and say, “the user experience isn't really this bad,”
as the problems reported will be as conservative as possible. Also, allowing users to
use their own technical environment makes it more likely that, as only one or two
new technical components are introduced to them, that you would have isolated the
impact of the new items. In an extreme situation, if users were presented with new
hardware, OS, application, and assistive technology at the same time, it would be
hard to isolate the impact of any of the individual technologies.
However, this situation of allowing users to utilize their own technical environ-
ment may not be possible if part of what is being evaluated in research is a new set
of technical configurations or applications. Another reason why allowing users to
utilize their own technical environment may not be possible, is because the research
involves a strict experimental design, and the technical environment needs to be con-
trolled for. It would be a confounding factor in experimental design, if each user
utilized a different technical environment. For instance, if a series of Deaf users had
different screen sizes for reading the captioning, or Blind users were using different
screen readers and listening at different rates of speech, these factors would clearly
not be controlled for in an experimental design. It is important for researchers to plan
ahead and consider if they want to allow users to utilize their own technical environ-
ment, or if they want to control the technical environment and make it consistent.

16.3.5 INTERVENTIONS
Researchers should consider when interventions, during data collection, may be ap-
propriate and how they should be documented. Interventions, as described in the
chapter on usability testing, are when there is an interface barrier that users are pre-
sented with, which does not allow the user to continue in the interface. These barri-
ers are often accessibility barriers. So, for instance, if a login screen or an interface
screen is inaccessible, it means that a participant with a disability may not be able
to continue to use the rest of the web site or application. Generally, if researchers do
not intervene, this means that the data collection is over, and that would be a missed
opportunity to learn more about other aspects of an interface or other portions of data
collection. An intervention is when a researcher helps the participant move forward
by providing advice. Before beginning any data collection involving people with
disabilities, a researcher should have a clear decision on if any interventions will be
allowed, under what circumstances, how they will be documented, and how this will
be accounted for in reporting the results.

16.4 LOGISTICS
16.4.1 COMMUNICATING WITH POTENTIAL PARTICIPANTS
When recruiting potential participants, it is important to understand their preferred
method of communication and any related challenges. For instance, email may not
be the preferred option for users with spinal cord injuries (SCI), as it may be harder