According to selectbs.com, 2013, structured Systems Analysis and Design Method (SSADM) is a systems approach to the analysis and design of information systems. SSADM was produced for a UK government office concerned with the use of technology in government, from 1980 onwards. The names “Structured Systems Analysis and Design Method” and “SSADM” are now Registered Trade Marks of the Office of Government Commerce (OGC), which is an Office of the United Kingdom’s Treasury.
System design methods are a discipline within the software development industry which seek to provide a framework for activity and the capture, storage, transformation and dissemination of information so as to enable the economic development of computer systems that are fit for purpose.
SSADM is a waterfall method by which an Information System design can be arrived at; SSADM can be thought to represent a pinnacle of the rigorous document-led approach to system design, and contrasts with more contemporary Rapid Application Development methods such as DSDM. SSADM is one particular implementation and builds on the work of different schools of development methods, some of the key members of which included:
Stage 0 – Feasibility study
In order to determine whether or not a given project is feasible, there must be some form of investigation into the goals and implications of the project.
For very small scale projects this may not be necessary at all as the scope of the project is easily understood. In larger projects, the feasibility may be done but in an informal sense, either because there is not time for a formal study or because the project is a “must-have” and will have to be done one way or the other. When a feasibility study is carried out, there are four main areas of consideration: Technical – is the project technically possible?
Financial – can the business afford to carry out the project? Organizational – will the new system be compatible with existing practices? Ethical – is the impact of the new system socially acceptable? To answer these questions, the feasibility study is effectively a condensed version of a fully blown systems analysis and design. The requirements and users are analyzed to some extent, some business options are drawn up and even some details of the technical implementation. The product of this stage is a formal feasibility study document. SSADM specifies the sections that the study should contain including any preliminary models that have been constructed and also details of rejected options and the reasons for their rejection.
Investigate the current environment
Draw a Data Flow Diagram (DFD) and Entity-Relationship Diagrams (ERDs) to show the current system.
Business Systems Options (BSOs)
Describe possible new systems in terms of functionality and implementation issues. Use text and skeletal DFDs and LDMs.
After choosing a BSO, refine DFDs and LDMs. To model how the system will respond to events (entity behavior modeling), draw an entity life history (ELH) diagram, an effect correspondence diagram (ECD), and enquiry access paths (EAP).
Technical System Options (TSOs)
Describe the costs, benefits, and constraints of implementing the specification.
Define how data is processed by the system and describe user dialogs. Update the entity life history diagrams with state indicators and draw an updated processing model (UPM).
Develop user interface structures and implement logical processes. (smartdraw.com, 2013)
selectbs.com, 2013 claims that the 3 most important techniques that are used in SSADM are: * Logical Data Modeling
* This is the process of identifying, modeling and documenting the data requirements of the system being designed. The data are separated into entities (things about which a business needs to record information) and relationships (the associations between the entities).
* Data Flow Modeling
* This is the process of identifying, modeling and documenting how data moves around an information system. Data Flow Modeling examines processes (activities that transform data from one form to another), data stores (the holding areas for data), external entities (what sends data into a system or receives data from a system), and data flows (routes by which data can flow).
* Entity Behavior Modeling
This is the process of identifying, modeling and documenting the events that affect each entity and the sequence in which these events occur. In this assignment, we decided to use SSADM as our methodology after comparing with the others two, the SDLC and OOAD. This is because we found that SSADM is more suitable for our case study which is building a system for monitoring aftercare program. We need the steps and stages to successfully found out the aim of our system and hence building it step by step. By using SSADM, we will use class diagram to show out every steps that we will take to build the system including the role and use of every person using the system.