Impact of Coupling and Cohesion on Software Maintainability

Abstract

Coupling and cohesion are important design properties that directly affect software maintainability, modification effort, testing complexity, and long-term code quality. High coupling creates strong dependency between modules, making changes in one component likely to affect other parts of the system, while low cohesion indicates that a module performs unrelated responsibilities and becomes harder to understand or modify. Traditional maintainability evaluation may focus on defect counts or code size, but these measures do not fully explain how internal module relationships influence maintenance difficulty. This article focuses on the impact of coupling and cohesion on software maintainability by examining dependency strength, module responsibility, interface complexity, change propagation, test effort, and refactoring need. The study discusses how low coupling and high cohesion can improve code readability, reduce regression risk, simplify debugging, and support flexible software evolution. The article concludes that careful management of coupling and cohesion is essential for building maintainable, scalable, and reliable software systems.