A system for improving the efficiency and reliability of entering data into a database or spreadsheet computer program by providing suggested completions to the data entry operator. The operator invokes an edit mode (200) for a particular data area and a dynamic list of possible completions is generated (210) based on other data items associated with the edited data area. The list of possible completions is dynamic because it changes to reflect the status of the current data within the database or spreadsheet. As the operator enters characters of a data item (220), the list of completed data items is searched for an entry that matches the entered data item (230). If a match is found then the matching item is displayed to the data entry operator as a suggested completion (240). The data entry operator can then elect to accept the suggested completion (250) or to continue entering the data item.