Selection Controls

Selection Controls

A selection control presents on the screen all the possible alternatives, conditions, or choices that may exist for an entity, property, or value.

The relevant item or items are selected from those displayed.

Selection controls include radio buttons, check boxes, list boxes, drop-down/pop-up list boxes, and palettes.

Radio Buttons

Description:

A two-part control consisting of the following:

—   Small circles, diamonds, or rectangles.

—   Choice descriptions.

When a choice is selected:

—   The option is highlighted.

—   Any existing choice is automatically unhighlighted and deselected.

Purpose:

To set one item from a small set of mutually exclusive options (2 to 8).

Advantages:

Easy-to-access choices.

Easy-to-compare choices.

Preferred by users.

Disadvantages:

Consume screen space.

Limited number of choices.

Proper usage:

For setting attributes, properties, or values.

For mutually exclusive choices (that is, only one can be selected).

Where adequate screen space is available.

Most useful for data and choices that are:

—   Discrete.

—   Small and fixed in number.

—   Not easily remembered.

—   In need of a textual description to meaningfully describe the alternatives.

—   Most easily understood when the alternatives can be seen together and

—   compared to one another.

—   Never changed in content.

Do not use:

—   For commands.

—   Singly to indicate the presence or absence of a state.

Choice Descriptions

Provide meaningful, fully spelled-out choice descriptions clearly describing the values or effects set by the radio buttons.

Display in a single line of text.

Display using mixed-case letters, using the sentence style.

Position descriptions to the right of the button. Separate them by at least one space from the button.

When a choice is conditionally unavailable for selection, display the choice description grayed out or dimmed.

Include a none choice if it adds clarity.

Size

Show a minimum of two choices, a maximum of eight.

Defaults

When the control possesses a state or affect that has been predetermined to have a higher probability of selection than the others, designate it as the default and display its button filled in.

When the control includes choices whose states cannot be predetermined, display all the buttons without setting a dot, or in the indeterminate state.

When a multiple selection includes choices whose states vary, display the buttons in another unique manner, or in the mixed value state.

Structure

A columnar orientation is the preferred manner of presentation.

Left-align the buttons and choice descriptions.

If vertical space on the screen is limited, orient the buttons horizontally.

Provide adequate separation between choices so that the buttons are associated with the proper description.

—   A distance equal to three spaces is usually sufficient.

Enclose the buttons in a border to visually strengthen the relationship they possess.

Organization

Arrange selections in expected order or follow other patterns such as frequency of occurrence, sequence of use, or importance.

For selections arrayed top to bottom, begin ordering at the top.

For selections arrayed left to right, begin ordering at the left.

If, under certain conditions, a choice is not available, display it subdued or less brightly than the available choices.