thesis - Faculty of Information and Communication Technologies ...

Chapter 7. Implications
contain new functionality (which is possible if new classes were created
due to refactoring), the consistency with which new classes are added
suggests that developers grow software systems by adding functionality
in new classes.
7.2 Software Development Practices
We now discuss some of the implications of our findings and offer recommendations
to help improve software development practices with a
specific focus on how maintenance activities can be improved by software
project managers, designers, testers and tool builders.
7.2.1 Project Management
Our results show that evolution proceeds by accumulation and combination
of stable intermediate states, suggesting that the stability plays
a role in ensuring successful evolution. In this context, stability implies
the observed strong boundaries in the metric distributions. This knowledge
can be directly used during project planning, specifically during
effort estimation. Consider a situation where a preliminary high-level
analysis of a new feature indicates the need for 50 new classes. We
know that it is highly likely that these 50 classes will not substantially
alter the overall shape and structure of the underlying distribution.
That is, we can use the size and complexity probability distribution
histograms to estimate the size and complexity distribution of these 50
classes which can be used as input into the effort estimation process.
Further, our findings also provide additional support for the recommendation
of collecting and using historical data to improve accuracy
of estimation.
Although substantive changes in Gini Coefficient values are rare, these
changes do happen. The real value for project managers is that this
knowledge can be used as a trigger to ensure that the rationale and impact
of changes are properly communicated. Furthermore, monitoring
trends in the Gini Coefficient values can reveal an unknown or poorly
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