An event is unpredictable if as a result, the system situation changes to unexpected, namely, when it gets outside of the design scope, and if there is no data hinting that this kind if transition is possible.
Unpredictable events are attributed to non-existence of data, for rare events.
In terms of the Black Swan theory ( Taleb ), unexpected events are called Black Swans.
Unexpected events
Updated on 02 Jan 2016.