Review paper on Coupling and Cohesion

software engineering (SE) has attempted to use software measures and models to reduce complexity, and thereby achieve other goals, such as greater productivity. However, complexity cannot always be reduced Coupling is usually contrasted with cohesion. Low coupling often correlates with high cohesion, and vice versa. Low coupling is often a sign of a wellstructured computer system and a good design, and when combined with high cohesion, supports the general goals of high readability and maintainability.Cohesion is an ordinal type of measurement and is usually described as “high cohesion” or “low cohesion”. Modules with high cohesion tend to be preferable because high cohesion is associated with several desirable traits of software including robustness, reliability, reusability, and understandability whereas low cohesion is associated with undesirable traits such as being difficult to maintain, test, reuse, and even understand. The objective of this paper is to understand how software design decisions affect the structural complexity of software. This is important because variations in the structural complexity of software can cause changes in managerial factors of interest, such as effort and quality.