Saturday, July 05, 2008


Responses should match the question

I’ve mentioned before, in passing, that when your computer asks you a question, the choices it offers for responses should be parallel to the question. Too often, the folks designing the pop-up box try to give the buttons sensible-seeming responses, in violation of this rule and at the expense of understandability.

Take, for example, this question you might get from Mac OS 10.5 if you use the Finder and drag a file from one folder to another:

An older item named [xxx] already exists in this location. Do you want to replace it with the newer one you are moving?

(Stop)       (Replace)

Now, without the question in the second sentence, “Stop” and “Replace” might be fine choices:

An older item named [xxx] already exists in this location.

(Stop)       (Replace)

...although I might prefer the admittedly longer “Do Not Replace” to “Stop”.

But they’ve added a yes/no question, and the cognitive disconnection in trying to sort out which response means “Yes” and which means “No” (or, alternatively, in trying to push out the question and just dealing with the statement in the first sentence) is jarring. If you ask a yes/no question, the response choices have to be “Yes” and “No” (in whichever order makes sense):

An older item named [xxx] already exists in this location. Do you want to replace it with the newer one you are moving?

(No)       (Yes)

Of course, the larger issue is that these dialogue boxes should be crafted carefully. They must ask straightforward questions that are easy to understand and that users can confidently and reliably answer. For example, this sort of formulation would be horrible:

An item named [xxx] was found in a search of this location in preparation for the move. You can continue, replacing the file, but data might be lost in the process. Do you want to stop?

(No)       (Yes)

Unfortunately, questions not too far from that show up far more often than one would like.


Thomas J. Brown said...

When one considers how important – and how easy – it is to implement good usability standards, I am constantly amazed that companies continue to allow the developers to write user interface copy.

It wouldn't be too terribly expensive to hire someone to craft well-written, easy-to-understand dialogues so that users aren't left scratching their heads.

The Ridger, FCD said...

Geoff Pullum once wrote about a dialog box that reads: Mail has been updated. Do you want to allow the new version to access the same keychain items (such as passwords) as the previous version?

This change is permanent and affects all keychain items used by Mail.

Don't Change. Change All.

His analysis is interesting.