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Transcript of A.I.S
Bringham Alabama F I F T H . E D I T I O N T W E L F T H . E D I T I O N Accounting information system Marshall B.Romney
Brigham Young University Paul J.Steinbart
Arizona State University The system development process -Introduction to system development system analysis
-AIS development strategies.
-Systems design , implementation and operation. System development life cycle Systems
design The System development life cycle System Analysis -Do initial investigation.
-Do systems survey.
-Do feasibility study.
-Determine information needs and
-Deliver systems requirements. Operations and Maintenance -Fine-tune and do post-implementation
-Do ongoing maintenance.
-Deliver improved system. Implementation and Conversion -Develop an implementation and conversion plan.
-Install hardware and software.
-Test the system.
-Convert from old to new system.
-Deliver operational system. Conceptual Design -identify and evaluate design alternatives .
-Develop design specifications.
-Deliver conceptual design requirements. Physical design -Design output.
-Deliver developed system.
-coordinates new information system development projects with the company's long range plans.
-Many companies employ a staff of strategic planners who advise top management and who identify and suggest long range goals,such as:
- Before beginning new development projects,theses people ensure that the new projects are consistent with the master plan Throughout the life cycle,planning must be done and behavioral aspects of change must be considered. Two system plans are needed:
1-Project development plan
2-master plan -During the system deesign ,the team translates recommendations made in systems analysis into a form that can be implemented.
-Two distict phases:
1-During preliminary design,the first phase,a
system is created conceptually .
2-Detailed Specification of the new system. -Once the information system committee approves the detailed specifications for the new system ,its implementation begins .
-personnel are trained in the new systemand if
necessary new personnel are hired.
-Any required new equipment is acquired and
-Any new forms or supplies required by the system
are ordered . -Review system operations
-System maintenance. F O U R T H . E D I T I O N Accounting
system Joseph W.Wilkinson
Bernard Wong-On-Wing *The 1st phase of systems development involves planning. It begins with long-range strategic planning and then leads into the planning of specific systems projects.
-strategic planning for information systems
Strategic system planning provides the overall guidance within which systems projects are planned and developed. Although not actually a part of SDLC, Strategic system planning enables a firm to avoid piecemeal, haphazard, & costly development of its information system. By looking ahead several years and spanning all of a firm's activities and functions, strategic systems planning attempt to
1- Integrate the information system development with the firm's overall planning processes.
2- Ensure orderly development of systems projects, making efficient use of available resources.
3- Recognize changing priorities and newly arising conditions as well as increasing informational demand.
4- Incorporate improvements in information technology as they become relevant to the firm's needs and promise greater benefits than the cost outlays. Steps in strategic systems planning
- Planning of systems projects
Systems development typically proceeds through a series of systems projects. These systems projects, which apply resources to specific areas within the information system, are established through strategic systems planning. Steps in the system analysis phase:
1) Survey of present system.
2) Analysis of survey findings.
3) Identification of system requirements.
4) Identification of information needs.
5) Submission of systems analysis report.
A system survey essentially has the purpose of documenting all relevant aspects of the current system. In doing so, the project team must confirm the scope of the project and gather a wide variety of data. A survey consists essentially of asking such questions as: what is done? How is it done? Where is it done? An analysis attempts to answer such searching questions as:
How well is it done? Should it be done at all? If so, is there a better way of doing it? Why is it being done? In effect, this portion of the systems analysis phase resembles a reengineering effort. The requirements relating to the physical system are determined in part by reference
1) To the analysis of the present system and its problems and
2) To expected future conditions.
They also are strongly affected by the objectives stated in the strategic systems plan and project proposal. In order to ensure that the system generates reports needed by managers, key employees, and outside parties, part of the requirements should consist of needed information. System analysis The system analysis phase of the SDLC represents an application of the systems approach to an organizational problem.
It consist of two steps
Preliminary survey consists of an evaluation of existing system or systems performed by a team of analyst from MIS and user departments
It has 4 obiectives
1.To acquire an understanding of existing
2.To develop good relationships with users of the
3.To collect data that are potentially useful in system design
4.To identify the nature of the problem being
The information system steering committee initiates the preliminary survey in response to system study proposal. •Reasons for proposal
1-Problems with an existing system.
2-New requirement for information.
3-Desire for new technology. Project initiation
The information system steering committee consist of the chief information officer and a representative from each user department.
The committee establishes priorities for the MIS staff,
If the proposal arises from problems with an existing system ,the committee evaluates the seriousness of the probem.
less serious problems such as those represented by minor inefficiencies may be deferred. Scope of preliminary survey
The purposes of the preliminary survey include developing an understanding of existing applications and available resources.
In conducting the survey,the system study team determines the following information about the existing system:
4.Internal control Methods of gathering data
6-Audit report. Feasibility study
The preliminary survey consist of an examination of existing system in contrast during the feasibility study the sytem team examines alternatives that are potential changes to existing system . System analyses Comparing costs and benefits
The study team evaluates the economic feasibility of a new system or system change by comparing the costs with the benefits by using one of three methods :
a.Net cost or benefit
b.Return on investment
c.Discounted cash flow The simplest way to compare costs and benefits is to subtract one from the other . when the benefits exceed coss , the study team calculates the net benefit. If benefits are less than costs , the result is a net cost.
Many people refer to this calculation as cost –benefit analysis
This form of analysis is appropriate when the study team is comparing annual costs with annual benefits, or one-time costs with one-time benefits. Some companies evaluate economic feasibility using return on investment (ROI)
ROI=annuals benefits – annual costs
One-time development costs
ROI is a popular measure but, like cost-benefit analysis , it ignore the time value of money. Discounted cash flow methods overcome this disadvantage. These methods of comparing costs and benefits recognize the importance of the timing of cash flows as well as their magnitudes, many new systems require a major one-time investment of cash during development and produce smaller annual benefits over many years.
The value to an organization of the annual benefit received this year is grater than an identical annual benefit received 10 years in the future .
because of this, the money saved or received over an extended period of time has time value. Contents of a system study report
1. Describe the problem , information need or desired technology
2. State the objective of the system study
3. Describe procedures followed in the preliminary survey
4. Identify the constraints on the problem solution
5. Discuss the two or three best system alternatives:
Identify the solution , its objectives and its scope
Describe advantages and disadvantages
Summarize financial costs and benefits
State major assumptions
6. Make a recommendation
Possibles outcomes of system analysis
1. Do nothing
2. Modify an existing system
3. Design a new system Approaches to systems development 1-Develpment by in-house IS department.
2-Outsourcing the system.
3-Prototyping. Approaches to system development 1-Top-down versus bottom-up approach Top-down approach:
-Begins at the top of the organization with the
overall objectives and strategies.
-The focus is on the overall organization and its
information needs for decision making.
-Thus the top-down approach is well suited as
an approach for developing decision-oriented
systems such as decision support system,
executive information systems, & expert
In contrast, the bottom-up approach
-begins at the bottom of the organization. It
focuses on the individual operations &
-This approach can continue the integrating process to form massive interlocking applications. For instance, purchasing and accounts payables applications may first be developed separately, then joined, and subsequently combined with production & shipping applications that form a large logistics application.
-Thus the bottom-up approach is suitable for developing transaction processing systems. 3- Reengineering approach:
-The reengineering approach focuses on a firm's operational processes.
-It takes a revolutionary view in that it is concerned with why a process is necessary rather than with the details of how it is done. By taking this view, systems analysts can often eliminate entire processes or portions of processes that don’t add value.
-. Even when processes are determined to be essential, the ways they are performed may be radically changed. Three major reasons dictate the need for continual systems development:
1- Changes inevitably occur.
2- Shortcomings arise or become apparent.
3- Improvements in information technology. Reasons dictate the need for continual systems development:
1- To respond to changes in user needs or business needs.
2- To take advantage of respond to technology changes.
3- To accommodate improvements in their business process.
4- To accommodate growth.
5- To accommodate downsizing or distribute decision making.
6- To gain a competitive advantage&/or lower costs.
7- To replace a system that's aged& unstable. It consists of 5 steps:
4.Information needs and systems requirments.
5.System analysis report. (1)Conceptual systems design:
- In the conceptual systems design phase, the
developer creates a general framework for:
**Implementing user requirements.
**solving problems identified in the analysis
There are three main steps in conceptual design
a) Evaluate design alternatives.
b) Prepare design specifications
c) Prepare conceptual systems design report. 2- Physical design:
Physical systems design includes the following activities:
(2)File and database design.
(6)Controls design. -In the systems design phase, the designer's task is to consider the features of an improved system that will satisfy the requirements. Since more than one set of features may be satisfactory, they must specify the particular set that appears to be best suited to the firm's circumstances, both present and future.
-The deliverable from the systems design phase, therefore, is a set of specifications that pertain to this best design.
-These design specifications are also subject to approval by the firm's management.
-The system design process involves two levels: Conceptual design and Detailed design. -Once management approves the design specifications of a system, the selection process can start.
-During the process of selecting needed hardware and software for a newly design system, the acquiring firm must consider the various acquisition options, proposals concerning hardware and software, and evaluate the proposals.
Both higher-level management& the project team will likely be involved in these steps. Accountants can also be involved, especially in the selection of software that pertains to financial processing applications. -After the evaluation team selects the needed system resources, a report is prepared and presented to management.
-. If approval to acquire the selected resources is given, the project then enters the implementation phase. Implementation a new information system design consists of three major steps:
1- Performing preliminary actions,
2- Executing activities leading to an operational system,
3-Conducting follow-up activities and evaluations (1) Preliminary Actions
-The implementation phase generally engages the efforts of many persons over a much longer period than the preceding phases combined.
-Frequently, it entails considerable costs. Therefore, several important actions should be taken before beginning the actual implementation activities. 1- Establish implementation plans and controls
Two key techniques often used for controlling systems projects are Grantt charts
and network diagrams.
2- Recognize behavioral concerns
3- Review the organization of the project team
4-complete arrangements for selected system resources. Step (2) Implementation Activities
The activities that take place during a systems implementation vary widely from project to project. Also, the sequences in which the activities are executed can't be standardized.