Usability Testing with Silverback…pretty slick

As part of my new job as ACT’s User Experience Designer, one of my jobs will be to do some usability testing of the websites we develop.  This is a brand new position to ACT, so in addition to educating people about what goes into User Experience Design/User Centered Design/Usability Engineering (the buzzwords change about every 5 years, it seems), I’m looking for a set of usability testing tools that I can use on projects.  This week, I’m playing with Silverback, a Mac-only usability testing tool from Clearleft.

Silverback has two things going for it.  Silverback itself is pretty simple.  It uses the computer’s webcam to record the user’s face, records all the screen activity (highlighting mouse clicks with a pleasing graphic), combines the two and exports a video of the test session into a Quicktime .mov file.  Second, at $50, it is crazy affordable.

So here’s how I set up my computer to do usability testing of a web site with Silverback.  I have a G5 Mac Pro with 2 monitors, and an old-school external iSight.

  • Turned off the second monitor
  • I reset the monitor resolution to 1024×768, which is what our weblogs show to be the most common aspect ratio.
  • I wanted to hide my desktop image, and all the cluttered documents on my desktop, so as not to distract participants.  A nifty donationware app called Camouflage took care of that.
  • I used Firefox as the browser for this usability study.  I created a new, blank Firefox profile specifically for this usability study.  To do this, you have to open the Terminal and invoke firefox with the commandline option –profilemanager.  I set the home page of this new profile to the page under study.  I added a couple bookmarks to the bookmark bar for a couple other pages I would ask participants to look at during the course of the study.
  • Start Silverback.  When participants arrived, I had them situate themselves in front of the computer and webcam, and started the Silverback recording session.  Participants performed the tasks I asked them to do, and Silverback records audio, video, and on-screen activity.
  • When they were done with the tasks, I stopped Silverback recording.  I then asked them to fill out a post-test questionnaire, which I was able to quickly set up using a Google Spreadsheet Form.
  • After the participant leaves, you can export the video file to .mov.  This can take awhile — about 2-3 hours for the 1/2 test sessions I ran.  File sizes range from 1-2GB per half/hour session (you can customize video sizes and other options that affect both size and speed of the export).

That’s basically it.  And that’s the point.  Silverback is designed to be a quick, inexpensive, fast, unobtrusive way to do usability testing, and I’d say they’ve made an excellent start.  I’ve gone from zero to a fully-functioning usability testing workstation in the time it takes to download the software.  If you’ve got a mac laptop with Apple Remote, you get to add bookmarks to the video so you can mark interesting events during the study.

I tried adding some feedback to their product customer service page, but I couldn’t get the site to work.  Some things I hope to see in future versions:

  • A preview of the audio levels…some way to make sure the user is speaking loudly enough, and that there isn’t too much background noise
  • It would be nice to have some facility for pre- and post-test questionnaires, demographics, etc.   Maybe keep a database of questions so that they can be resued in subsequent tests.

Anyway, congratulations to the staff at Clearleft.  They’ve got my $50, and I look forward to future iterations of Silverback.


One thought on “Usability Testing with Silverback…pretty slick

  1. Thanks very much for taking the time to share your experiences, I’ve been meaning to start doing my own usability testing and this article has given me a bit more confidence to get started.

    One way you could solve the problems with the volume levels would be to buy MacSpeech Dictate — as it has an unobtrusive volume indicator on the screen whenever it’s running. It’s a bit pricey if you only need to see the volume levels (~$300). I’m using it right now to dictate this response, and if you practice with it you can dictate at about 160 words a minute. The quality of the audio would be very high, and as it uses a boom microphone it wouldn’t matter if the subject turned their head whilst they were talking.

    Is there any chance you would reveal the contents of your post-test questionnaire?


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