The Shlaer–Mellor method, also known as Object-Oriented Systems Analysis (OOSA) or Object-Oriented Analysis (OOA) is an object-oriented software development methodology introduced by Sally Shlaer and Stephen Mellor in 1988. The method makes the documented analysis so precise that it is possible to implement the analysis model directly by translation to the target architecture, rather than by elaborating model changes through a series of more platform-specific models. In the new millennium the Shlaer–Mellor method has migrated to the UML notation, becoming Executable UML. Overview The Shlaer–Mellor method is one of a number of software development methodologies which arrived in the late 1980s. Most familiar were Object-Oriented Analysis and Design (OOAD) by Grady Booch, Object Modeling Technique (OMT) by James Rumbaugh, Object-Oriented Software Engineering by Ivar Jacobson and Object-Oriented Analysis (OOA) by Shlaer and Mellor. These methods had adopted a new object-oriented paradigm to overcome the established weaknesses in the existing structured analysis and structured design (SASD) methods of the 1960s and 1970s. Of these well-known problems, Shlaer and Mellor chose to address: The complexity of designs generated through the use of structured analysis and structured design (SASD) methods. The problem of maintaining analysis and design documentation over time. Before publication of their second book in 1991 Shlaer and Mellor had stopped naming their method "Object-Oriented Systems Analysis" in favor of just "Object-Oriented Analysis". The method started focusing on the concept of Recursive Design (RD), which enabled the automated translation aspect of the method. What makes Shlaer–Mellor unique among the object-oriented methods is: the degree to which object-oriented semantic decomposition is taken, the precision of the Shlaer–Mellor Notation used to express the analysis, and the defined behavior of that analysis model at run-time. The general solution taken by the object-oriented analysis and design methods to these particular problems with structured analysis and design, was to switch from functional decomposition to semantic decomposition. For example, one can describe the control of a passenger train as: load passengers, close doors, start train, stop train, open doors, unload passengers. Then a design becomes focused on the behavior of doors, brakes, and passengers, and how those objects (doors, brakes, etc.) are related and behave within the passenger train domain. Other objects, that provide services used by the passenger train domain, are modeled in other domains connected to the passenger train domain. Shlaer–Mellor method topics Translation v. elaboration The goal of the Shlaer–Mellor method is to make