How do people find items in a list?
When people see a list, they want to understand its organization. If it isn’t alphabetical, the order should be clear and related to the information and the task. You want your users thinking about the contents of the list, not its presentation.
I’ve seen different types of problems when usability study participants were looking for information in lists. Here are some:
- A participant looked at a list of database field names that were ordered by the date they were added. He said, “There’s no order to these fields, so I have to fight this every day.”
- Another participant sarcastically referred to the “alphabetized list of our 1000-plus reports”. While it was alphabetical, there were too many items to scroll through. A hierarchical list, or an easy way to remove old reports, or some filtering methods would have helped him.
- In a related study, there was a long list that was organized hierarchically, but it was shown in a very small window. It was like looking into a busy room through a keyhole – people could see a little bit of information at a time, but never get a good feeling for the list as a whole.
- Looking at an online discussion, a participant in another study remarked that he wanted to see “a threaded-message view”, which is another form of hierarchy. It was as a flat list, where it was hard to tell whether a message was a topic, a response or a response to a response.
- Search engines generally show results sorted by relevance. In the early days of search, results included a relevance indicator (e.g., a bar whose length shows the relevance of each result). This isn’t used any more because, as we saw in usability testing, they weren’t meaningful to users.
- Another recent study showed the top five items in a couple of categories. Some participants wondered how the list was put together. It could have been editorial choice, most-viewed or most-emailed. Understanding the source of the list would affect how they interpreted it.
Jakob Nielsen, in his Alertbox column wrote about a number of cases where alphabetical order isn’t the best choice, and other situations where alphabetical order was used, but presented in such a way that it wasn’t clear. Good points that illustrate the need to find the right order and present it in the right way.
One thing to take into account is how people will use the list. Understanding how each user type (or persona) approaches the task can help you decide to use alphabetical order, form groups that create a hierarchy, or find an order specific to your use.