Choice from a Small Set
Set of radio buttons
Combo box (drop-down list)
"Circle one: Mr / Mrs / Ms" on a paper form
Old-fashioned car radio with the mechanical buttons
Automatic transmission shift
Set of toggled light switches (not the push-button kind)
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.
Some modern car radios that don't show you which button was last selected
Problem: How should the artifact indicate what kind
of information should be supplied?
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.
The user should see all the possible values, to put the actual value in
If the user needs to set the value (not just look at it), they should know
what choices are available.
Small numbers of things can be taken stock of quickly, and don't take up
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: email@example.com
Last modified May 17, 1999
Copyright (c) 1999 by Jenifer Tidwell. All rights reserved.