Does your usability lab need a one-way mirror?
When HumanCentric moved into our new building in 2008, I was part of the team that designed our usability lab. One-way mirrors were an essential part of the design of the rooms. However, when our UK Partner in the International UX Partners, Amberlight, redesigned their usability lab in 2008, they didn't use
any mirrors, and our German partner, UID, also has a usability lab
without mirrors. This article will help you decide if you need one or not.
If you decide to install a one-way mirror, you should read my article,
How to build a one-way mirror.
What is a one-way mirror?
It's glass that has been coated with a thin
layer of metal so that it's reflective, like a mirror. It's called a
one-way mirror because in one direction it's a mirror, but in the other
direction it's a window. There's some debate about the proper name.
Many people call it a two-way mirror because either side can be used as a
mirror by changing which room is lit and which room is dark. They're
commonly used in usability labs and focus group rooms, but also in
police lineup and interrogation rooms, observation rooms for day care
facilities, and to hide a television in your home when not in use.
Advantages of a one-way mirror
- Capture of interactions - you can see all of the
emotions on the face of the participant, their body language, and their
interactions with both the product and moderator.
- Wide view - you can see the entire room and session
context, and are not limited to places that the camera can see. For
studies that involve large products or moving around the room, camera
views can be very restrictive. For example, we worked with Whirlpool,
whose lab is a full kitchen with a mirrored wall; watching someone move
around the kitchen through a camera is just not the same.
- Makes you focus - there is something compelling
about watching actual people that captures your attention; with video,
is is easier to get distracted from the session. Although the huge flat-panel TV screens you can get today are more captivating than smaller screens used to be.
- No equipment needed - once the mirror is installed,
no equipment is necessary to use it, which means no equipment to break
or software to crash during a session, and training for the moderator is minimal.
- Showcase - one-way mirrors look cool and are great for tours.
Advantages of no mirror
- Flexible study room - no need to orient toward the mirror location, or dedicate a wall of the room to a mirror.
- Mirrors make people nervous - some participants
notice the mirror and ask about observers behind it, although most
quickly forget about it, especially if we have the flexibility to face
them away from the mirror. To be fair, you can mitigate this by placing
mini-blinds or sheer curtains in front of the mirror, and the cameras in
rooms without a mirror make people almost as nervous as the mirror.
- Flexible view - your point of view can be from
anywhere you can place a camera, although you can set up similar
observation monitors even with a one-way mirror.
- No dedicated observation room - there is no need to
dedicate a room as an observation room when you are watching via video
streaming. This is great when space is at a premium. Our study rooms do
get used as meeting rooms, but our observation rooms are only used for
one purpose.
- Lit observation room - you can keep the lights on
for taking notes or having a meeting, or sit in a room with windows that
aren't blocked by blackout curtains. This helps keep the observers awake,
and makes them more likely to interact with each other and less likely to multi-task.
- Sound proofing - it is difficult to design a
one-way mirror that is as sound proof as a wall, and even if you do
sound may still travel between adjacent rooms. If you have rowdy
observers or your observers want to have a working meeting during the
sessions, you can pick a room that is physically distant from the study room
so participants cannot hear.
Do you have to have a one-way mirror?
No, you do not have to have it.
At HumanCentric we had it because we wanted to show it off to clients, and because we did a lot of evaluations of physical products, some that were really large. Our European consulting partners never use them because space is too precious, and some of the buildings they work in are really old.
When I set up our lab at BB&T we used video streaming instead of a mirror because space was at a premium and our rooms needed to be flexible. Also, we
did mostly software and mobile evaluations, and it was too expensive for the benefit. We have a 60" TV in our observation room, and everyone loves to come watch sessions because they have a lot of fun in the observation room - you could never do that with a mirror for fear of noise issues.
If you decide to install a one-way mirror, you should read my article,
How to build a one-way mirror.