Structured System Analysis and Design Method - Essay Example

Structured System Analysis and Design Method (SSADM) Number Structured System Analysis and Design Method (SSADM) Structured systems Analysis and Design Method (SSADM) is an approach to the design and analysis of information systems that was first introduced in the UK in the 1980s and has been in use since then. The name itself is registered trademark of the United Kingdom’s office of commerce. System design paradigms are a fundamental area of software design that is intended to provide a framework for capturing, storing, manipulation and dissemination of information (Downs & Coe, 1992). Structured System Analysis and Design Method. Is a Development method that emphasizes on the detailed system development that entails a sequence of steps for analysis, documentation and the design of an information system. SSADM is an implementation that particularly combines different school of thoughts postulated by different schools of development, authors and scholars (Hutchings, 2001). These schools of developments structure design projects into well defined and small activities and also give the sequence and interaction of these activities. SSADM also uses modeling techniques and diagrammatic techniques to specify structured definitions that can be easily comprehended by the developers as well as the system users (Chaffey, 1999). Advantages of using a structured method The SSADM is a method that is more structured and detailed and provides a better platform for the development of information systems. Due to its attributes the structured method has several advantages compared with other design and analysis methods (The Government of the Hong Kong special Region, 1998). Structured system analysis and design method always provides a requirements statement that is always clear and understandable. This provides a foundation for the analysis design and the implementation of the system. This is mainly achieved through the use of simple language and use of diagrammatic descriptions (E & E, 1988). This method also allows for more utilization of both experienced and inexperienced staff in an organization for the design process. All staff can be assigned various tasks and responsibilities with the inexperienced staff given the less demanding tasks and are guided by the experienced or expert staff (Hawryszkiewycz & Igor, 1995). Structured method also guarantees a more improved project planning and control. The breaking don of the project into phases enables division of labour and effective estimation of project duration and management. Errors and flows can also be easily identified and rectified before moving to the next stage (Hawryszkiewycz I. T., 1995). Better Quality systems. Comprehensive definition of system requirements in structured design allows the design and production of a high quality system. This use of structured techniques has been proven to yield flexible and dynamic systems that are amenable to change (Hawryszkiewycz I. T., 1995). Additionally structured methods have been attributed to characteristics which include;the segregation of the physical and logical design, user involvement in the analysis and design process and quality assurance (ocij, Chaffey, Greasley, & Hickie, 1999). According to (Robbins, 1991) the method is also highly practical and offers a coherent design. This is attributed to it’s emphasize on data analysis that ensures proper scrutiny of the system to be developed thus providing a highly practical and coherent method of information systems analysis and design. Disadvantages of using structured method The major problem associated with the structured method is the time and cost involved. There is always a delay in the inception and the delivery of the project. This is due to the thoroughness that is involved during the analysis and the design of the information system (Krallmann, 1994). Difficulties can also be experienced due to the rigidity associated with this method. Project data may change at any point in the project cycle, the data that is collected and analyzed during the analysis stage of the system will thus lead to incorrect system if the data is changed after the analysis has been completed (Downs & Coe, 1992). Phases of SSADM The SSADM addresses the system development from a holistic approach which involves two major stages that are further broken down to form six phases of development. The two major stages are the system analysis which essential defines what is to be done, and system design which defines how things will be done (Chaffey, 1999). a) System analysis stage/ feasibility study. The system analysis stage entails the assessment of the current situation and coming to consensus with the users and all stakeholders and coming up with a detailed specification of user requirements and the levels of user services and performance (Hutchings, 2001). The phases in this stage of SSADM include: i) An analysis of the system operations and the problems. The current system is analyzed to determine how the operations are conducted, what hardware, software and data is used to carry out these operations and the respective personnel that are responsible for handling the various operations in the system. It also involves the determination of the problems in the current systems. This is then presented in form of DFD (Data flow diagram) (Hutchings, 2001). ii) Specification of the requirements that the system to be designed must provide to the organization. This phase focuses on what the system does and not how to achieve the objectives. The current scenario and the system requirements are modeled using DFDs and Logical data structure for the data and processes that constitute the system. The management has to make informed decisions therefore BSOs describing both scope and functionality by a certain approach are presented to them. These options are mainly supported by technical documentation including work practice model, logical data model. Financial and risk assessments are also prepared and presented to them (E & E, 1988). This stage also entails the selection of technical options. Here the user selects from a list of options the implementation strategies that have different cost implications, service levels and development implications (Chaffey, 1999). b) System design stage. This stage mainly defines the system to do the desired as identified in the analysis stage and provides a plan on how this is to be implemented. The phases in this stage include: i) Data design phase/ logical design. Here the logical system specification is done; logical designs and processes are updated in this phase the user dialogues are defined, update processes, and enquiry processes are defined (E & E, 1988). ii) Physical design phase. The logical design is converted to an implementation on a particular hardware and software platform is defined and specified to performance requirements. The main objective is specification of physical data and process design using the language and features of the identified physical environment and the standards for installation (Krallmann, 1994). This stage also entails preparation of physical design, completion of specification of functions and incrementally and repeatedly develops the data and process designs. iii) Input & Output of SSADM Each and every organization has varied technical requirements and also specific requirements for the system. This always acts as input of SSADM therefore it is right to say that the input of SSADM is varied thus there in no specific input of SSADM. The input of SSADM is in form of a start up document that contains all the system requirements and specification that eventually lessens the efforts at the analysis stage (Hutchings, 2001). However the inputs to SSADM include; Project initiation document: Business case Entails the description of the current business scenario and the processes that take place in the current business environment. These include, operations, activities and software and hardware in the system and the personnel involved in the accomplishment of this tasks and operations. It also includes the specifications and the user requirements that are stated by the users (Downs & Coe, 1992). Terms of reference The terms of reference entails the specifications from the client about what is needed by the client and the system requirements. Project boundaries The scope of the system and what is needed by the client in order to achieve the objectives set during the project requirement specification. Project management A statement of the time and resources that are needed to accomplish each step of the design from the conception to completion and submission of the project. Reports from previous Studies. Feasibility Report. The feasibility reports from the previous studies also act as an input to the SSADM. The information is IS Strategy Report. The outputs from the system include: Program specifications Database and file specifications User procedure specifications Operations procedure specifications. Key techniques used in SSADM with respect to System diagrams The three key techniques used in SSAD include: a) Logical data modeling. This technique identifies, models, and documents the process and data requirements of the system being designed. The output from this technique is a data model comprising of entities attributes and relationships. The entities are items things or objects about which information and data is collected and kept about. The attributes define or describe these entities, whilst association between these entities, forms the relationships (ocij, Chaffey, Greasley, & Hickie, 1999). The figures below show the symbols that are used for the entities, attributes and relationships respectively. Entity Attribute Relationship b) Data Flow modeling This technique models and represents how data moves around an information system. This is done using the Data Flow diagram which examines processes, data stores, external entities and data flows. Processes are the activities which transform data to different forms, Data stores holds areas for the data to be used in the information system, external entities sends information into the systems or receives information from the system, data flows are the routes through which data is transmitted (ocij, Chaffey, Greasley, & Hickie, 1999). The diagrams below represent these concepts: Process External entity Data store c) Entity Event Modeling. Entity behavior modeling identifying, modeling and documenting the events that may affect each entity and the order or sequence through which these events occur. The modeling for each of these events and the processes to co-ordinate entity history (ocij, Chaffey, Greasley, & Hickie, 1999). References Chaffey, D. (1999). Business Information Systems. England: Prentice Hal. Downs, C., & Coe. (1992). SSADM: Application and Context. Prentice Hall. E, K. K., & E, K. J. (1988). Systems Analysis & Design, Prentice Hall, 1988. Prentice Hall. Hawryszkiewycz, & Igor, T. (1995). System analyse and -design. England: Prentice Hall. Hawryszkiewycz, I. T. (1995). Systemanalyse and -design,. England Hutchings: Prentice Hall. Hutchings, T. (2001). Introduction to Methodologies and SSADM . Krallmann, H. (1994). Systemanalyse im Unternehmen,. Oldenbourg Verlag, München. ocij, P., Chaffey, D., Greasley, A., & Hickie, S. (1999). Business Information Systems. England: Prentice Hall. Robbins, S. P. (1991). Organizational Behaviour: concepts, controversies and applications. Prentice-Hall. The Government of the Hong Kong special Region. (1998). An introduction to Structured Systems Analysis & Design Methodology (SSADM). Retrieved March 2, 2013, from The Government of the Hong Kong special Region: Read More