Phase 1: - (Systems Planning) - This is probably the most important step since it is the start of the project and will include every detail. The systems planning phase usually begins with a formal request to the IT department, called systems request, which describes problems or desired changes in an information system or a business process. The purpose of this phase is to perform a preliminary investigation to evaluate an IT related business opportunity or problem. The preliminary examination is a critical step because the outcome will affect the entire development process. A key part of the preliminary investigation is a feasibility study that reviews anticipated costs and benefits and recommends a course of action based on operational, technical, economic, and time factors.
Phase 2 - (Systems Analysis) - The purpose of this phase is to build a logical model of the new system. The first step requirements modeling, where you investigate business processes and document what the new system must do to satisfy users. Requirements modeling continues the investigation that began during the systems planning phase. The deliverable for the systems analysis phase is the system requirements document. The system requirements document describes management and user requirements, costs and benefits, and outlines alternative development strategies.
Phase 3 - (Systems Design) - The purpose of this phase is to create a physical model that will satisfy all documented requirements for the system. At this stage, you design the user interface and identify necessary outputs, inputs, processes, internal and external controls, computer based and manual features to guarantee that the system will be reliable, accurate, maintainable, and secure. The deliverable for this phase is the system design specification, which presented to management and users for review and approval. Management and user involvement is critical to avoid any misunderstanding about what the new system will do, how it will do it, and what it will cost.
Phase 4 - (Systems Implementation) - The objective of this phase is to deliver a completely functioning and documented information system. During this stage, the new system is constructed. If the system was purchased as a package, systems analysts configure the software and perform any necessary modifications. At the conclusion of this phase, the system is ready to use. Final preparations include converting data to the new system's files, training users, and performing the actual transition to the new system. This phase also includes an assessment, called a systems evaluation, to determine whether the system operates properly and if costs and benefits are within expectations.
Phase 5 - (Systems Support and Security) - During this phase the IT staff maintains , enhances, and protects the system. Maintenance changes correct errors and adapt to changes in the environment, such as tax rates. Enhancements provide new features and benefits. The objective during this phase is to maximize return on the IT investment. A well-designed system must be secure, reliable, maintainable, and scalable. A scalable design can expand to meet new business requirements and volumes. Information systems development is always a work in progress. Business processes change rapidly, and most information systems need to be updated significantly or replaced after several years.