Understanding HCI

User control and freedom

In general, protect users from mistakes and give them the freedom and power to undo a mistake when they make one. The system should adapt to the needs of the user not the reverse

Don't make important irreversible actions easy to perform

Pressing a delete button should not delete the item straight away. Instead, ask the user to confirm that they do in fact want to delete the item.

You should also remind them that it may not be possible to undo the delete action once completed.

Offer undo and redo options

If possible, allow the user to start over, undo or edit the last action, and redo actions they have already completed.

Provide clearly marked "emergency exit" signs

When inside an interface, have a clearly identifiable EXIT or HOME button. This give the user a level of comfort that they can leave when they choose, without having to navigate to an exit point.

Ask for 'confirmation' whenever you can, without being annoying or overprotective

This is a difficult balance to achieve. The level of confirmation you might require from the user may depend on whether they are novice, expert or intermediate users.

Further Reading