Key points are not available for this paper at this time.
Data on the history of seven systems was analysed to statistically test the 5 laws of software evolution proposed first by Belady and Lehman in 1976.While there was some evidence supporting laws 1 and 2, laws 3-5 were not supported by the data. In the light of the result a new discontinuous model of software evolution is proposed to replace the smoothly changing continuous model proposed by Lehman.
Michael Lawrence (1982) studied this question.