Rule Definition
Excessive coupling between objects is detrimental to modular design and prevents reuse.
The larger the number of couples, the higher the sensitivity to changes in other parts of the design and therefore the more difficult the maintenance.
Remediation
High CBO numbers might indicate that a class has too many responsibilities. Such a class is potential candidate for a refactoring where the class would delegate some the responsibilities to other classes or new classes (Extract Class, Extract Method refactoring). This will increase modularity and reusability.
When refactoring with architecture in mind, the CBO metric can be used to check classes running on the application client that have high coupling.
Reference
A Metrics Suite for Object Oriented Design
Chidamber, S.R. and C.F. Kemerer
IEEE Transactions on Software Engineering, 1994
Related Technologies
Technical Criterion
Architecture - Object-level Dependencies
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