Tuesday, March 18, 2014

Useful Statistics about Maintainability

Here are some useful statistics collected from several papers:

  • Approximately, 70% of software programs are identifiers. Therefore, identifiers names are of paramount importance for readability
Unused Features: From this paper:
  • Jim Johnson (the Standish Group) in his keynote at XP2012 reports that 45% of the features in the analyzed systems were never used
  • Industrial business information system showed that 28% of its features were never used
  • 25% of all method genealogies were never used
Code Clones and defects: Some very useful statistics from this paper: Do code clones matter?:
  • 52% of code clones are inconsistent
  • of these inconsistencies, 28% are introduced unintentionally, and 18% are faults in the system
  • Overall, 10% of code clones are defective
  • 9%-19% conformance of implementation to architecture, 72%-90% of these non-conformances are due to flaws in documentation
  • 10%-28% decay in architecture
  • 20% effort increase in maintenance due to code clones

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