There are two kinds of dialog box which require the user to confirm an action:
Non-Destructive Action
(POPUP_TO_CONFIRM_ STEP or POPUP_TO_ CONFIRM_WITH_VALUE, Pre-Selected Response: "Yes")
In this case, you should consider whether the dialog box is really necessary, as it will slow down processing.


Dialog box for confirming a non-destructive action
Procedure
Layout
Further Examples of Questions
Destructive Action
(POPUP_TO_CONFIRM_ STEP or POPUP_TO_ CONFIRM_WITH_VALUE Pre-Selected Response: "Yes" or "No")
If the destructive operation may have irreversable consequences, a dialog box should always be displayed. For example, the user has selected 20 lines in a list and then chooses
Delete.Should Response Option "Yes" or "No" be Selected?
If a transaction offers several operations of euqal priority which require the user to confirm the action, and some of these operations are of a destructive and others of a non-destructive nature, the "Yes" option can be the pre-selected response for all operations. In these unusual circumstances the "Yes" option is pre-selected for a destructive action.
If, however, the destructive operation is the less frequently used function, then the "No" response should be pre-selected to provide for maximum protection against a loss of data.


Dialog box for the confirmation of a destructive action
Procedure
Layout
Further Examples of Questions