Blooper 9: One-from-N settings with no initial value

Images from GUI Bloopers, by Jeff Johnson. Used without permission.

What's wrong with these?

• Radiobutton settings that initially have none of the radiobuttons selected (not a good idea). It violates users' expectations about how a radiobutton choice should operate. It also violates the logical type of a radiobutton set: a one-from-N choice, not a zero-or-one-from-N choice.

• Option menus with no initial value. Like radiobuttons, option menus are for representing one-from-N choices. Starting them with a blank value is starting them with an invalid value, unless one of the values available in the menu for users to choose is blank.

Design Rule: Avoiding this blooper

Following the above example, if an application needs to allow users to indicate that they don't want any cheese on their pizza, then the radiobutton set should include a fourth explicit value: "None", as is shown below

Alternatively, the entire setting could have an associated checkbox that, when unchecked, deactivates the radiobutton choice (i.e., causes it to be displayed with a grayed-out appearance and not be responsive) and, when checked activates it (this is recommended only when it's used consistently throughout an application).

Similarly, if a designer of an online questionanaire doesn't want to bias users' answers by picking one of the possible answers to each question as a default value, the designer should add an explicit "no opinion" value to each setting and make those the defaults..