The understanding and management of complexity is perhaps the most important task of the designer of an information system. It is carried out bearing in mind the strategies of abstraction as well as hierarchical ordering (divide & conquer).
In the real world, an accounting information systems designer (systems designer for short) is rarely called upon to analyse and design a system from the scratch. Usually, such a system does exist, but the client (user) is not quite satisfied with it. The systems designer starts with the documentation of the existing accounting system, if it does not exist. Often, documentation pertaining to the existing system is contained in the audit workpapers pertaining to the auditor's study of control risk assessment. However, since such documentation is not prepared with a view to design a system, it is used only as a starting point in building the documentation to aid systems design.
In this document, we shall study how abstraction and hierarchical ordering strategies are used to manage the complexity of analysing and designing the functions of an information system.