RESEARCH ARTICLE
No Silver Bullet – The Evolutionary Model

ABSTRACT

This paper’s objective is to present an evolutionary model that better explains the behavior of the gap between software engineering (SE) essence difficulties and SE capabilities, and adds an evolutionary dimension to Brooks’s approach regarding the gap. In his 1987 landmark paper, Brooks argues that software projects incorporate inherent essence-conceptual difficulties that are unchanging and irreducible. He concludes that SE developments hardly contribute to SE capabilities to handle SE essence difficulties. Thus, there is no solution to SE essence difficulties. In Brooks’ words, “there is no silver bullet (SB)”, as the gap between SE essence difficulties and SE capabilities, (hereafter named “the SB gap”), is unchangeable and irreducible. We argue that the SB gap is the result of two evolutionary processes, that affect SE simultaneously: (a) continuously growing SE essence difficulties and (b) continuously growing SE capabilities. Thus, the size of the gap is not irreducible and unchangeable as in Brooks’s argument. Periods of rapid SE development, rapid growth of SE capabilities may cause a reduced size of the gap. However, in periods where economic developments cause a higher growth rate of SE essence difficulties, a larger gap may result. It is noteworthy that the smaller the gap, the better the software development performance is in terms of reliability, productivity and simplicity.

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