Object orientation offers the following benefits:

• Encapsulation of design decisions
• Increased modularity limiting the effects of changes in requirements
• Improved communication resulting in a more effective application structure
• Additional mechanisms for re-use

In structured software modeling an analysis would have to be transformed into a design. Using the UML (Unified Modeling Language), an object-oriented analysis can be elaborated into an object-oriented design through the addition of extra detail. Therefore, not only can the analysis and design be performed in the same notation, they can be performed concurrently.

Object-oriented analysis

In object-oriented software the main building block is the object. An object is generally drawn from the vocabulary of the problem domain, and has an identity, state, and behavior. This combination of state and behavior allows an object to be modeled directly from the physical entity it represents. On a larger scale, this enables the entire problem domain to be abstracted and modeled.

Object-oriented analysis examines requirements from the perspective of the objects found in the vocabulary of the problem domain.

Object-oriented design

Object-oriented design performs decomposition in an object-oriented fashion to depict a system as a series of logical, physical, static, and dynamic models. Recommended design methods, e.g. design patterns, help define a proper and effective structure for a complex system. Using these techniques help manage the inherent dependencies between software modules - making the software easier to change, and localizing defects - producing systems that can be maintained and enhanced over their lifetime.