For a C# project of mine the code metrics delta after a refactoring are:
- Maintability Index: -4
- Cyclomatic Complexity: -48
- Depth of Inheritance: 0
- Class Coupling: -9
- Lines of Code: -85
How come the Maintainability Index has decreased when the formula is:
MI = MAX(0,(171 – 5.2 * ln(Halstead Volume) – 0.23 * (Cyclomatic Complexity) – 16.2 * ln(Lines of Code))*100 / 171) ?
Possible options: 1) the Halstead volume has increased; 2) you use a MI-variant that takes comments in to account.