Systems Analysis and Design Overview

Systems analysis and design has existed since the beginning of time. It is a problem solving technique that involves a series of logical steps to provide a solution to a problem, implement the solution, and test the solution against the original problem. Several methodologies have been developed over time to provide a framework for this process including the traditional, prototyping, and end-user development methodologies.

Each of these methodologies follow the same general steps, however, the differences in each approach are in how each treats these steps. There are six basic steps to systems analysis and design (called the systems life cycle):

  1. preliminary investigation
  2. systems analysis
  3. systems design
  4. systems development
  5. systems implementation
  6. systems maintenance

The traditional approach follows these steps rigorously. Similar to the actions of a waterfall, the traditional approach proceeds to the next step when the current one has been completed and approved by the user. The prototyping approach repeats (reiterates) steps 1-4, adding more detail with each pass, and involving the user at each stage. End-user development provides support, often in the way of a help desk or development support group, to the user who in turn follows the steps of the systems life cycle.


Preliminary Investigation

In the preliminary investigation the analyst isolates the problem statement and determines the system requirements. The system requirements are stated as terms of reference which are measurable statements that will be used for the systems audit during the systems maintenance step. Factors that may affect a possible solution are detailed under the environmental headings:

The preliminary investigation step concludes in the traditional approach with the Preliminary Investigation Report. The purpose of this report is to define the problem, and to establish whether a solution may be possible. The report is presented to the users for ratification with a recommendation to either continue with the project or stop. In the prototyping approach the Preliminary Investigation Report is incorporated into a series of smaller reports, and in the end-user development approach it is often replaced with a less formal report.

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Systems Analysis

The systems analysis begins with the acceptance of the preliminary investigation report. In this step the analyst follows various flows through the system including:

Only data flows and process flows are dealt with in introductory systems analysis and design. The data is modeled to help establish what is important in the system, and to understand the relationships among the data entities. The systems analysis step concludes with an Analysis Report which is presented to the users for validation. The purpose of the report is to document the processes of the current system, detail the strengths and weaknesses of the current system, and provide a thorough understanding of the system and how the problem relates to the system processes. The recommendation of the report is to continue with the project, or stop, and the reasons must be adequately supported. This is the end of introductory systems analysis and design.

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Systems Design

The systems design step is not included in introductory systems analysis and design. This step consists of adding, changing and deleting processes to produce a new system. There are two major stages in systems design:

  1. logical design
  2. physical design

The logical design is independent of the physical world. It considers the processes only, not who or what does the processes or how the processes are completed. Most beginning analysts make their fatal mistakes here by assuming physical characteristics, such as, what will be computerized, what will be manual, etc. The logical design is only interested in what processes occur and in what sequence. The logical design must be approved by the user before proceeding further.

The physical design adds the physical characteristics to an approved logical design. This is where the people/machine interface is decided. What processes would best be automated, either by machine or computer, and what processes should be manual. The physical design must be approved by the user before proceeding further.

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Systems Development

Systems development is where the new system is built. Coding, documentation, and manuals are produced in this step. Testing of the system should be planned as an on-going process. The acquisition of hardware necessary for the new system is planned and ordered to coincide with the anticipated implementation of the system.

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Systems Implementation

During systems implementation personnel are trained in the processes of the new system, including operating procedures for new equipment, and the conversion from the existing system to the new system is planned. Possible types of conversion are:

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Systems Maintenance

Systems maintenance involves a systems audit and periodic reviews. Failings in the system are identified and corrected, and the system is matched against the objectives of the organization to determine if a new systems analysis and design process should be implemented, or if the system is functioning within the current parameters. During the systems audit, the system is compared operationally with the original design specifications.

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