So recently, I’ve been working on a mini-usability design study by asking users to do a card sort. In the process, I found some interesting tidbits.
What’s a Card Sort?
For those who don’t know what a card sort is, you basically put ideas (i.e. possible links to pages) on index cards or sticky notes and ask people (usually in a group) to sort them into categories, either existing ones you provide or ones that they name after.
Number of People to Test
Interestingly, I found that some articles suggested 25-30 people, but according to Nielson‘s correlation study, 15 is enough and after 20, it’s not worth the resources.
Card Sort Methodology
Open-sort vs. Closed-sort: We decided to use a close sort (categories are pre-determined) since we had already created a proposed information architecture (i.e. navigation structure).
Group vs. Individual: I had originally planned to do individual sessions since that would be more flexible, but J. (a coworker) has read studies about how these sorts of exercises work better in a group. I have read in various articles that group card sorts is the preferred method, so that made sense.
Silent vs. not: J. also suggested a silent card sort, which really did affect the group dynamic. I could see that even when silent there were people who were more assertive than others and that during the discussion that followed, those people were definitely more opinionated as well. So, I’m glad we did it as a silent sort.
Scheduling was definitely much more time consuming than I had thought it would be. And trying to find faculty was the most difficult. Perhaps due to the incentive that we provided ($10 for 30 mins), we had plenty of student volunteers, especially grads (probably because they were around whereas undergrads were less likely to be as it’s between the two summer terms). For faculty, our hardest-to-get group, personal e-mails were definitely necessary! (and from someone they know).
Getting people to think in the right mind frame was also an interesting task. A number of people who participated kept thinking about the design. Although it brings up interesting points which are helpful while we design a new site, some of it was irrelevant. Some kept thinking that it would be the home page, but no… it is not. They got the idea that what they saw was definitely going to be on the website, but that’s not true either. It got a bit frustrating at times, because I would basically say, “yes, good point, but let’s focus on the task at hand” (which was the card sort itself and naming the categories). Most of the time it worked, but with one or two people… somehow that didn’t. They were so focused on “this is what and how I would like to see the website to be”, so I had to repeat more than once that it’s not the home page, just a single page somewhere. I got around it by turning my open questions into closed questions, but man… argumentative people can definitely change the group dynamics and totally veer the discussion in a totally different direction. Okay… apologies… </rant> But I think it brings up the important point that having a good mediator/facilitator is very important. I honestly think that my coworker would have done a better job than I did, but ah well, you do what you can.
Backup plans are a must-have! What if something goes wrong? Terrible on my part, I know, I did not really think about it before the actual sessions took place. What do you if someone doesn’t show up? What if more people suddenly show up? Does it matter to your study? I decided that for our purposes, if one person give or take in a group wasn’t a big deal, but definitely something to think about next time. Making sure you have all needed materials and back-up materials if things break down is also another much needed consideration.
Another Online Resource
Finally, there were a lot of good online resources. In particular, Spencer & Warfel’s Guide is quite comprehensive.