SSADM, or Structured Systems Analysis and Design Method, is a sophisticated approach to the analysis and design of information systems. An information system is the combined working of people and specific set of hardware and software for the purpose of enhancing the operation of an organisation. SSADM is like an instructional manual of step-by-step guidelines the analyst can follow. SSADM guides analysts through the process of developing information systems for an organisation.
SSADM has detailed rules and guidelines that lead the analyst from one suggestion to another regarding the proposed information system. Following the SSADM rules and guidelines, an analyst may have to examine documentations related to the proposed information system. He may also have to interview the people who are to make use of the information system about what they require for the system. Thus SSADM makes the analyst consider many vital details related to the proposed information system.
A logical and coherent presentation of what the designer requires for the design of the information system will make the designer's work easier. SSADM leads the analyst to set out such a logical presentation. Due to its logical system, SSADM emphasises information analysis and includes such techniques as data flow program. Information analysis is the process of a thorough analysis of alternative sources of information; organisations need to include information analysis in their information systems because it will oblige them always consider alternative means of getting desired information. A data flow program, on the other hand, represents the flow of information within the information system and between the system and its environment (i.e., individuals and groups with whom the organisation shares or exchanges information).
Taken together, the seven stages of the SSADM form a set of practical prescriptions that take real conditions and challenges into consideration. They allow the designer to think realistically about the proposed information system. Some of these seven stages are feasibility study (the first stage) and study existing system (the second). Feasibility study asks the designer to consider if the proposed information system is realisable. Study existing system asks her to review existing systems, if there are any, before designing a new one; this will ensure that all proposed changes to the old system are necessary and useful.