Sunday, December 2, 2012

Usability problem of the day (Scrabble)

In the courses I teach about human-computer interaction, I typically open each class with an example of a usability problem. I'm putting these online, in case others find them useful.

This is how the Scrabble app on my iPhone worked for some time (the current interface has gone through a few revisions). Let's walk through it.

I decide that I want to play a game of Scrabble. When I start up the app, this screen appears.

 I touch "Play!" of course. "Play!" is probably the most common action for all users, and it's appropriate for it to be the top item in the menu.

Hmm... I'm not yet Play!ing. I need to decide with whom I'd like to play: the computer, Facebook friends, or other friends with phones nearby. I touch "Local Play", as I always do. Again, it's at the top of the menu.

But I'm still not playing! I almost never have time to finish an entire game--I just play when I'm bored--and I always start a new game. The message is badly phrased, in that it's asking me a question and then immediately explains what will happen if I say, "No." (Better might be two options: "Start new game" and "Resume current game," leaving explanations for the Help screen.) I touch "Yes," thinking, "How many times do I have to say I want to play a game?"

Game Setup? I didn't ask for this. I read through the menu, but I don't see a "Play" option. Wait, there it is--a button in the top right corner of the screen. I touch "Play", and I can finally start playing a game.

I can use this example to encourage students to think about a few different issues.

  • Generally speaking, when we're considering the tradeoff between effort and results, we want the most common results to involve the least effort. That's not obviously the case here.
  • "Effort" includes touching targets, and a large body of theoretical and empirical research tells us that smaller targets are harder to touch without error and that they take longer to touch accurately.
  • The Scrabble app merges two different styles of interaction. One is menu-based, the other navigation-based. (That is, notice that as you walk through the screens, you can choose to go backward by touching the "Back" button on the top left.) The integration is awkward here.
  • Focus of visual attention can be important even on the small display of a mobile device. I carry out a few actions in a row by looking at the information in the center of the screen; there's nothing that tells me I will need a visual search elsewhere to find out what to do next.

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