Usability vs. Discoverability
I came across this very interesting piece on the distinction between useability and discoverability the other day. It’s brings up some really good points and is well worth a read. He defines discoverability to affect how long it takes a new user to perform a specific task and he defines useability to be how efficiently a user can continue to use that feature. It is a distinction I’ve long made for UI in that sometimes you optimize for the novice user and sometimes you optimize for the returning user. In this way, I often use message boards as an good example. Threaded boards optimize for the new user - it presents the entire conversation, more or less as it happened, so it’s very easy to go and follow distinct trails of discussion. However, if you are a consistent user of that board it is worse because it makes it difficult to simply find out what conversation has occurred since you were last there.
At any rate, if you accept his definitions then he walks down a very well thought out line of reasoning where he makes the case that business apps don’t need discoverability as your more common web2.0 apps do, since they’ll be operated at length by seasoned users. It is more important to optimize for the veteran user, in that case.
My problem is that I don’t necessarily accept that useability and discoverability are orthogonal. That is, I think good usability implies good discoverability. I think there is another type of efficiency he is talking about where you can reduce usability but increase the efficiency of repeat users. For example, the text editor VI (or VIM as I like to use) is a perfect case of this. Once you have internalized how to use the editor it is, IMO, the best text editor there is for straight text. You can move around really quickly, but the commands and environment in which you do so are not text book cases of clear design. They are kind of obfuscated and simply require you to remember things. I’d say it scores poorly on discoverability and poorly as well on general useability but scores very highly on efficiency.
He gives as his example that discoverability is the equivalent of putting a button for every function necessary, which for things like Office apps is prohibitive. But, in my view, that does nothing for discoverability or for usability. Having tons of buttons makes it more difficult to discover things, a much cleaner menu/paletting system allows for organization and discoverability. This also increases the useability. Adding in keyboard shortcuts on all those menu items thus also increases the efficiency of the veteran user.
It’s quite a good article and gets you thinking about design and UI issues. I guess the most important thing to keep in mind is who your target audience is. From that should flow your UI.
