Choice from a Small Set

Examples: Bad Examples: Context:  The artifact shows, or allows the user to set, a value which is one out of a small set of possible values (10 or fewer).   This often happens on Forms and Control Panels, and sometimes on Status Displays; it is very similar to Choice from a Large Set.

Problem:  How should the artifact indicate what kind of information should be supplied?

Forces:

Solution:  Show all the possible choices up front, show clearly which choice(s) have been made, and indicate unequivocally whether one or several values can be chosen.  Provide a choice for "Other" or "None of the above," if that will ever be an issue -- don't prevent a user from providing correct information, if they're in a better position to know what's "correct" than you are.

Resulting Context:  Good Defaults may let the user look at the default value, judge it to be OK, and move on without even bothering to set the value.  If the choices are pictorial, or are cryptic in some other way, Short Description may be needed to describe the choices further.

With physical or electronic artifacts (i.e. not paper), a single selection can be enforced by causing the previous choice to "unselect" when the next choice is made. Old car radios did this, and GUI radio boxes do it as well. A user will normally discover and understand this very quickly.
 
Notes:  The "10 or fewer" comes from Miller's number (see Small Groups of Related Things). For such a small number, it is often pointless to hide the choices, such as in a combo box -- if it won't cost a huge amount of space, you might as well show all the possibilities so the user can see them without going through an extra step to reveal them.


Comments to:  jtidwell@alum.mit.edu
Last modified May 17, 1999

Copyright (c) 1999 by Jenifer Tidwell.  All rights reserved.