Importance of Requirement Bell Labs and IBM:80%of all product defects are inserted in the requirement definition stage of product development (Hooks and Farray 2001). Software does not fail randomly.Software malfunction is due to design error,which most of the time are due to incomplete/incorrect requirements (Leveson 2012) System Engineering by J.J.Gao CLGO 7+ - System Engineering by J. J. Gao 7 Importance of Requirement