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April 11, 2012 The joys of mobile usability testing Tracy Godding, Head of UX Research

The joys of mobile usability testing

There are so many blog posts about the logistics of carrying out mobile usability testing it can be difficult to see the wood from the trees. When I was planning the testing for our new mobile web app I ended up going around in circles to research the best method and set-up to use. Mobile testing can be problematic in terms of ergonomics, cost and efficiency. We've done a couple of rounds of testing now and I think I've reached a pretty good solution for us. So I thought I would add to all those posts out there but hopefully share something that sums up prevalent problems and helps with a solution.

There are 2 main problems to solve; the set up of the hand held device (making it as natural as possible and easy to record) and technically how to record both interaction with the phone and facial expression. The latter is made easier if you have Morae version 3 which records a 2 camera set-up but not everyone has the budget for this.

I decided to use a plastic sled to mount the phone and camera. This came from fellow Brightonian and User Experiencer Harry Brignall in his blog post about making a sled for mobile testing. I made sure the sled was light, clear and slightly narrower than the average width of a smart phone. The angle of the bend was just over 45 degrees, so a camera could be fixed easily to record the user interacting with the phone. (Handy that my brother is in the plastic moulding business but Harry Brignall suggests using a toaster to mould the plastic).

Mobile phone sled made of plastic

I used a HUE web camera which is small, flexible, cute and relatively affordable at £40. It's pretty adaptable as the base can be removed; so it can stand nicely on a desk or if you remove the base can be attached to a device using a USB extension lead.

Next, as I already knew the types of smart phones my participants would use (targeting), I purchased simple plastic cases. I was then able to velcro the cases to the sled using double sided velcro tabs. This way I could just slip in the users phone without worrying about damaging or leaving unsightly stickiness on their precious phone. (Word of warning here - don't get silicone cases as nothing sticks to silicone!).

When the camera arrived I attached it to the top of the phone and realised this produced an upside down image (doh)! So I fixed it to the bottom instead. This actually works better, as I was able to angle it to the left so that it didn't interfere with their view and it presented a better position for recording, as their thumbs and fingers don't get in the way as much. (It would need to be positioned to the right if a left handed participant). Of course this also meant that I didn't actually need the plastic sled to have an angled portion above - it could be just a less intrusive straight piece of plastic. Although, I think having it leaves you the ability to change your options in the future - some cameras do swivel so could be used above the phone. (Also Morae has an invert image functionality).

Mobile testing rig

For capturing both the user's interaction with the phone and their expression I used a 2 camera set up with a Phillips web cam on the desktop. The software used was Microsoft Expressions Encoder 4 which has a screen capture/recorder and a manager, similar to Morae. Initially I tried the free download version but this only records for ten minutes at a time - so it was necessary to upgrade to the Pro version which was about £150. The trick here is to connect the HUE webcam to the encoder screen capture and have the desktop camera running through Amcap's (free) screen capture software. You can then have the Amcap window open on the desktop at whatever size you want and define this as the desktop region to record with the tool in the Encoder screen capture. Below is an example of what a recorded testing session would look like on playback in a media player.

Screenshot shwoing 2 camera set up using Encoder software

So there we have it. This set-up worked well for us and also didn't swallow up all our research budget.