The Structured Systems Analysis and Design Method, or SSADM, is an approach to designing and analyzing information systems. Developed in Britain in 1980, this method uses logical data modeling, entity event modeling and data flow modeling in a six-step process to determine how a system must be created or updated. This long and complicated analysis has multiple advantages and disadvantages.
One advantage of SSADM is its use of three techniques to determine information system viability. Logical data modeling determines the entities -- and the relationships between them -- in the system. Data flow modeling determines the ways in which data changes from one form to another, the holding areas for the data, the entities that send data into the system and the routes through which the data flows. Entity event modeling documents how events within the business affect the entities of the information system. When these three methodologies and viewpoints are provided, the model is more accurate and complete.
Such a deep and through analysis of a system greatly reduces the chance of any information being misunderstood at the beginning stages of the project. This can occur in systems that have inadequate analysis and poorly thought-out design. Also, since SSADM is used frequently, most people involved in the project will understand the process. Using a familiar process prevents the need to train new staff and saves both money and time.
The SSADM is a very structured method of creating information systems. It exercises control over every aspect of the creation process. This control is one of the major reasons it has become the standard, because it leaves very little room for error. This rigidity, however, can also lead to difficulties. It is inevitable that the requirements for the system will change at some point during development. SSADM is built on the analysis of data. If this data changes after the SSADM analysis has already taken place, the system recommended by the data may be incorrect.
The biggest drawback of the SSADM system is that it takes a great deal of time. When a business takes so much time to analyze the project, it may make it difficult to create the information system by a desired end date. There is a large delay between the inception of the project and the delivery of the system. If any employees of a company are not trained in the SSADM techniques, the company will need to spend even more time and money training them in this difficult system.