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Usability testing with participants who have special needs
Apr 2013

Usability testing with participants who have special needs

This was not our first time conducting usability tests with people with special needs but after this most recent experience, we felt it is important to share some precautions to consider when embarking on this journey.

Our projects have addressed people with diverse needs: some tests targeted the elderly with health conditions, others were aimed at illiterate individuals, while others concerned web site accessibility for the cognitively impaired and the physically disabled. The physically disabled participant used a virtual mouse along with an aid to interact with the keyboard*.

* This participant uses a special mouth-held stick that is gripped by his teeth to interact with the keyboard. Additionally, with special software installed, he uses a virtual mouse that is mapped to a small dot projected on glasses. He moves his head to control the mouse position.

Four(4) elements are considered to carry out tests of this nature.


The contact person
Interviewees do not always know what a usability test is. A poor introduction can leave them feeling intimidated, confused and/or nervous about being evaluated.
A contact person who knows the participant and has already established a relationship with him will reassure him, guide him and introduce him to the project team. The contact person should provide all the necessary information so that the team can anticipate the needs of the participant and address them (e.g. type of disability, history, what to do / not to do, contact in case of withdrawal, etc.).
Ideally, the contact person should be present during the interviews.


Flexible setup
It is not uncommon for participants to use tools that are beyond the traditional screen-keyboard-mouse/mobile phone.
The participant manipulating the keyboard with a stick he held between his teeth, for example, required the keyboard to be safely raised to type. Otherwise he would have had to lean in an awkward position to reach the keys. The same person used a virtual mouse that required the installation of software on the computer that was also running the testing software.The test set up (space, materials, lighting, temperature, etc.) must be flexible enough to adapt to various situations. For example, the test location and path to get there, including the doorways, must be wide enough to allow a wheelchair to pass through. A room with a well-moderated temperature may suit most individuals well, but could be too warm for those with certain health conditions. Offering to turn on a fan is a good idea for these participants.Take special care to reproduce realistic conditions. For example, if a participant would normally carry out a similar task with glasses, be sure that he brings the glasses to the test and wears them as he would normally. Likewise, if possible, provide the type of screen, resolution and lighting that the participant would typically use.

Transportation – moving around – accessing the space
Even if the equipment used in the testing laboratory meets the needs of the participants (screen size, layout position, accessibility of the room and the office, installed software, etc..), access to premises can also be problematic.
For example, safe alternatives to stairs (elevators, ramps, etc.) are essential for participants with reduced mobility. Further, a person with certain disabilities may require a paratransit service or at the least a taxi service. Receiving these participants at the door as they exit the taxi is ideal when possible. Considering all of this, it can be wise to allocate extra budget and time, with fewer tests per day.


Test Length
Pilot testing will not reveal all the challenges because different disabilities or health conditions will call for different accommodations. Furthermore, considering the above-mentioned logistics and reduced availability, it can be difficult to conduct pre-tests with these participants. So, to anticipate any possible delays, allocate at least 1.5 hours instead of the typical 60-minute test period.

Discussion Guide
In addition to the above-mentioned challenges, each task may take more time than usual either to set up or carry out. Again, for this reason it is best to allocate more time for the test session and in between test sessions (e.g. 1.5 hr interview + 30 minute gap between interviews).
As always, prioritize the most important tasks and be prepared to simply drop the last few tasks if need be.
Finally, you should ideally validate the discussion guide with the contact person to ensure that all terminology used will be understood.

Participants may not admit to not understanding instructions and may still try to complete the task. As such the moderator should empathize (without falling into compassion) and ensure that the instructions are clear and understood. The moderator can ask the participant to shortly explain the task to confirm that it was understood. If it wasn’t the moderator can reformulate the instructions.


When usability testing includes a very small number of participants with specific needs (e.g. people with two very different needs), it is not easy to generalize the results. This data should be treated separately and often cannot be generalized with the data of the other participants who do not have special needs.


We have seen that the “time factor” is relevant at each stage of the project – during test preparation, the test session itself, and the analysis of the results. Clearly time is a key element not to be overlooked with tests of this kind.
Allocating more time should not be a hindrance when conducting such tests. The little extra time can make the difference between completing a session or not.
Some participants with special needs take the interface design very seriously because issues can have an exponential effect on their experience. They feel more involved and when the tool is essential to their lives, their input is extremely useful.
They pay careful attention to detail, especially at first-level information because any unnecessary interactions can be physically and/or cognitively costly.
Ex 1: Automatically placing the cursor in the first field of a form with good visibility is significantly helpful for a person who interacts with a keyboard using a mouth-held stick. Likewise, large target sizes for buttons decreases effort and saves time.
Ex 2: Poor contrast and character size can slow the exploration and understanding of an interface for the visually impaired, in many cases affecting the elderly.
Ex 3: Excessive information on the page can easily derail participants. Whether it is accounting for those with visual impairments or those with interaction challenges, a sleek, minimalist page significantly improves the navigation experience.

Usability testing with people with special needs can be challenging but the rewards definitely are worth the effort.

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