The document discusses various code quality metrics that can be used to understand software quality, including defects density, unit test density, code and test coverage, cyclomatic complexity, fan-in and fan-out, and WTFs per minute. While metrics can help identify issues, they cannot determine the precise cause. Metrics should be used carefully to avoid incentivizing behaviors like hiding bugs. Maintaining pride in craftsmanship is important for quality.

1. Agile Code Quality MetricsGil Nahmias, CSP

2. Summary for ExpertsTools‘Metrics’ eclipse plugin

3. Ndepend

4. SourceMonitor

5. KlocworkMetricsWTF/MinuteAbstractness vs. InstabilityCyclomatic complexityTest cases/ClassDefect DensityFan in, Fan outCode coverage, Test coverage

6. “Metrics are a carving knife when what you really need is a scalpel. Metrics can tell you something is wrong, but they can't give you much guidance about the precise cause.disclaimerIn the case of clean code, the cause is discipline and professionalism”...”Fixing that problem is a matter of instilling pride of workmanship into the team” -- Uncle Bob

7. Note before we startWhat are we trying to understandWhat we actually measureHow does it make people behave

8. Note before we startWhat are we trying to understandWhat we actually measureSoftware Quality# of bugsHow does it make people behaveNot record bugsHidden bugs, long stabilization, poor quality

9. Note before we startWhat are we trying to understandWhat we actually measureSoftware QualityEscaping DefectsHow does it make people behaveHidden bugs, long stabilization, poor quality

10. WTF/Minute – in code reviewosnews.com/comics

11. Abstractness vs. instabilityblog.troytuttle.com

12. Software qualityDefect Density: number of defects per lines of codeUnit test density: number of unit test cases per feature or class.+ve (actual = expected) -ve (actual != expected) stress integrationMINIMUM4