1. Keying codes, such as airport codes when making a flight reservation, instead
of whole words on entry screens. Codes are also keyed when using a commandlanguage
interface, such as a two-letter state postal abbreviation. On a GUI
screen, the codes may be entered by selecting descriptions of the codes from a
pull-down list of available options. This helps to ensure accuracy, since the
code is stored as a value of the drop-down list, as well as helping to provide
meaningful communication since descriptions that are familiar to the user
are selected. An example would be selecting a Canadian province and having
the two-character postal code stored.
2. Entering only data that are not already stored on files. For example, when
changing or deleting item records, only the item number should be entered.
The computer responds by displaying descriptive information that is currently
stored on the item file. Another example is when a user logs on to a Web site,
the userID is used to find related records, such as a customer record, outstanding
bills, orders, and so on.
3. Supplying the editing characters (for example, slashes as date field separators).
Users should not have to enter formatting characters such as leading
zeros, commas, or a decimal point when entering a dollar amount; nor should
they have to enter slashes or hyphens when entering a date. In general,Web
sites are an exception to this rule, since Web forms do not include slashes or
decimal points. Some Web forms use a series of entry fields with editing characters
between them, such as parentheses around an area code.
4. Using default values for fields on entry screens. Defaults are used when a user
enters the same value in a screen field for the majority of the records being
processed. The value is displayed, and the user may press the Enter key to