The System Development Cycle (SDLC)


Suppose the chief executive of a firm where you are the sales manager asks you to find a better way to get information to the salespeople in the company. How would you start? What would you do? Would you just plunge ahead and hope you could come up with a reasonable solution? How would you know whether his solution was a good one for your company? Do you think there might me a systematic way to help you develop a good solution to your chief executive’s requests? There is. It’s a problems-solving process called the systems approach.

The system approach to problem solving uses a system orientation to define problems and opportunities and develop solutions. Figure 4.1 illustrates, studying a problem and formulating a solution involves the following interrelated activities.

  • Recognize and define a problem or opportunity in a system context.
  • Develop and evaluate alternative system solutions.
  • Select the system solution that best meets the requirements.
  • Design the selected system solution so that it meets the requirements.
  • Implement and evaluate the success of the designed system.

Let’s now examine each step of the systems approach to problem solving to see how it can help you develop system solutions to business problems.

4.1.1. Recognize and define a problem or opportunities in a system context: Problems and opportunities are identified in the first step of the system approach. A problem
can be defined as a basic condition that is causing undesirable results. An opportunity is a basic condition that presents the potential for desirable results. Symptoms must be separated from problems. Symptoms
are merely signals of an underlying cause or problem.


Symptoms: Sales of a company’ products are declining.

Salespersons are losing orders because they cannot get current information on product prices and availability.

Opportunity: Sales could be increased significantly if salespersons could receive instant responses to requests for price quotations and product availability.

Understanding a problem or opportunity in a system context is one of the most important aspects of the system approach. When you use a system context, you try to find systems, subsystems, and components of systems in the situation you are studying. This ensures that important factors and their interrelationships are considered. This is known as having a systematic view of a situation.

4.1.2. Develop and evaluate alternative system solutions: There are usually several different ways to solve any problem or pursue any opportunity. Jumping immediately from problem definition to a single solution is not a good idea. It limits the options and robs the chance to consider the advantages and disadvantages of several alternatives. And also lose the chance to combine the best points of several alternative solutions.

Alternative solutions may comes from the sources of-


-The solutions that have worked, or at least been considered in the past, should be considering again.

-Advice from others, including the recommendations of consultants

-The suggestions of expert system.

-Use of intuition and ingenuity (cleverness) to come up with a number of creative solutions.

Then more realistic alternatives that recognize the limited financial, personnel and other resources of most organizations could be developed.

4.1.3. Select the system solution that best meets the requirements: Once alternative solutions have been developed, they must be evaluated so that the best solution can be identified. The goal of evaluation is to determine how well each alternative solution meets business and personal requirements. These requirements are key characteristics and capabilities that you fell are necessary for your personal or business success. Evaluation criteria may be ranked or weighted, based on their importance in meeting of requirements. For example, you might rank a criterion concerning operating costs higher than a criterion of ease of use. Finally, each alternative solution must be evaluated based on how well it meets your evaluation criteria.

Once all alternative solutions have been evaluated, then begin the process of selecting the best solution. Alternative solutions can be compared to each other because they have been evaluated the same criteria. It is possible that you might not select the top-ranked alternative. A lower-ranked solution could be chosen for a variety of other reasons. For example, unforeseen budget constraints, political developments, or legal challenges may disqualify top choice. Or, all proposed alternatives could be rejected. In this case, new alternative solutions must be identified and evaluated.

4.1.4. Design the selected system solution so that it meets the requirements: Once a solution has been selected, it must be designed. You may have to depend on other business end users and technical staff to help you develop design specification and an implementation plan. Typically, design specifications might describe the detailed characteristics and capabilities of the people, hardware, software, and data resources and information system activities needed by new system.

4.1.5. Implement and evaluate the success of the designed system: Once a solution has been designed, it must be implemented. Implementation plans specify the resources, activities, and timing needed for proper implementation. For example, the following items might be included in the design specifications and implementation plan for a computer-based sales support system.

  • Types and sources of computer hardware and software to be acquired.
  • Operating procedures for the new sales system.
  • Training of sales personnel.
  • Conversion procedures and timetable for final implementation.

The final step of the system approach recognizes that an implemented solution can fall to solve the problem for which it was developed. Therefore, the results of implementing a solution should be monitored and evaluated. This is called a post implementation review process, since the success of a solution is reviewed after it is implemented. The focus of this step is to determine if the implemented solution has indeed helped the firm and selected subsystem meet their system objectives. If not, the system approach assumes you will cycle back to a previous step and make another attempt to find a workable solution.


Developing information system solutions to business problems is a major responsibility of today’s managers. They are responsible for proposing or developing new or improved information systems for their organizations. They must also frequently manage the development efforts of information systems specialists and other end users. This discussion builds on the problem-solving concepts in the previous discussion to show you how information system solutions that meet the business needs of end users and their organizations can be developed.

The System Development Cycle (SDLC)

When the system approach to problem solving is applied to the development of information system solutions to business problems, it is called information systems development or application development. Most computer based information systems are conceived, designed, and implemented using some form of systematic development process. In this process, end users and information specialists design information systems based on an analysis of the information requirements of an organization. Thus, a major part of this process is known as systems analysis and design. However, as the figure 4.2 shows, several other major activities are involved in a compete development cycle.

When the system approach is applied to the development of information system solutions, a multistep process or cycle emerges. This is frequently called the systems development cycle, or system development life cycle (SDLC). Figure 4.3 summarizes what goes on in each stage of the traditional information systems development cycle, which includes the steps of (i) investigation (ii) analysis (iii) design (iv) implementation, and (v) maintenance.

You should realize, however, that all of the activities involved are highly related and interdependent. Therefore, in actual practice, several development activities can occur at the same time. So, different parts of a development projects can be at different stages of the development cycle. In addition, analysis may recycle back at any time to repeat previous activities in order to modify and improve a system they are developing.

3.6.1. System Investigation

Do you have a business problem (or opportunity)? What is causing the problem? Would a new or improved information system help solve the problem? What would be a feasible information system solution to our problem? These are the questions that have to be answered in the system investigation stage- the first step in the system development process. This stage includes the screening, selection, and preliminary study of proposed information system solutions to business problems.

a. Information Systems Planning: The investigation stage may involve the study of information systems development proposals generated by a formal information systems planning process. A formal information systems planning process that is part of the regular business planning process of the organization is highly desirable. There are, typically, many opportunities to use information systems to support an organization’s end users and its business operations, management decision making, and strategic objectives. However, in the real world, end users, departments, and the organization itself have only limited amounts of human and financial resources to allocate to the development of new information systems, no matter how desirable they may be. Therefore, business and information systems planning helps to generate, screen, and select potential information systems for development.

b. Feasibility Studies: Because the process of developing a major information system can be costly, the systems investigation stage frequently requires a preliminary study called a feasibility study. A feasibility study is a preliminary study to investigate the information needs of prospective users and determine the resource requirements, costs, benefits, and feasibility of a proposed project. The methods of gathering information summarized in figure 4.4 are used to collect data for a feasibility study. The findings of this study are usually formalized in a written report. It includes preliminary specifications and a developmental plan for the proposed system. This report is submitted to the management of the firm for its approval before development can begin. If management approves the recommendations of the feasibility study, the systems analysis stage can begin.

  • Interviews with employees, customers, and managers.
  • Questionnaires to appropriate end users in the organization.
  • Personal observation or involvement in business operations.
  • Examination of documents, reports, procedures manuals, and other documentation.
  • Development, manipulation, and observation of a model of the business operations.

Figure 4.4 : Ways of gather information for systems development.

i. Cost/Benefit Analysis: Feasibility studies, involve cost/benefit analysis. If costs and benefits can be quantified, they are called tangible; if not, they are called intangible. Examples of tangible costs are the costs of hardware and software, employee salaries, and other quantifiable costs needed to develop and implement, as IS solution. Intangible costs are difficult to quantify; they include the loss of customer goodwill or employee morale caused by errors and disruptions arising from the installation of a new system.

Tangible benefits
are favorable results, such as the decrease in payroll costs caused by a reduction in personnel or a decrease in inventory carrying costs caused by a reduction in inventory. Intangible benefits
are harder to estimate. Such benefits as better customer service or faster and more accurate information for management fall into this category. Figure 4.5
lists typical tangible and intangible benefits with examples. Possible tangible and intangible costs would be the opposite of each benefit shown.

Tangible Benefits


Increase in sales or profits.

Developing of computer-based products and services.

Decrease in information processing costs.

Eliminate of unnecessary procedures and documents.

Decrease in operating costs.

Reduction in inventory carrying costs

Decrease in required investment.

Decrease in inventory investment required

Increased operational ability and efficiency

Improvement in production ability and efficiency, for example, less spoilage, waste, and idle time.

Intangible Benefits


New or improved information availability

More timely and accurate information and new types of information

Improved abilities in computation and analysis

Analytical modeling

Improved customer service

More timely service response

Improved employee morale

Elimination of burdensome and boring job tasks

Improved management decision making

Better information and decision analysis

Improved competitive position

Systems which lock in customers and suppliers

Improved business and community image

Progressive image as perceived by customers, suppliers, and investors.

Figure 4.5 : Possible benefits of customer-based information systems, with examples.

ii. The Feasibility of a System: The goal of feasibility studies is to evaluate alternative systems and to propose the most feasible and desirable systems for development. The feasibility of a proposed system can be evaluated in terms of four major categories, as illustrated in figure 4.6.

Organizational Feasibility

Economic Feasibility

How well the proposed system support the strategic objectives of the organization

Cost savings

Increased revenue

Decreased investment

Increased profits

Technical Feasibility

Operational Feasibility

Hardware and software capability, reliability, and availability

End user acceptance

Management support

Customer supplier, and government requirements.

Figure 4.6 : Organizational, economic, technical, and operational feasibility factors.

  • The focus of organizational feasibility is on how well a proposed information system supports the objectives of the organization and its strategic plan for information systems. For example, projects that do not directly contribute to meeting an organization’s strategic objectives are typically not funded.
  • Economic feasibility is concerned with whether expected cost savings, increased revenue, increased profits, reductions in required investment, and other type of benefits will expected the costs of developing and operating a proposed system. For example, if a project can’t cover its development costs, it won’t be approved, unless mandated by government regulations or other considerations.
  • Technical feasibility can be demonstrated if reliable hardware and software capable of meeting the needs of a proposed system can be acquired or developed by the business in the required time.
  • Finally, operational feasibility is the willingness and ability of the management, employees, customers, suppliers, and others to operate, use, and support a proposed system. For example, if the software for a new system is too difficult to use, employees may make too many errors and avoid using it. Thus, it would fail to show operational feasibility.

3.6.2. System Analysis

What is system analysis? Whether you want to develop a new application quickly or are involved in a long-term project, you will need to perform several basic activities of a systems analysis. Many of these activities are an extension of those used in conducting a feasibility study. Some of the same information-gathering methods are used, plus some new tools that we will discuss shortly. However, systems analysis is not a preliminary study. It is an in-depth study of end-user information needs that produces functional requirements that are used as the basis for the design of a new information system. Systems analysis traditionally involves a detailed study of:

  • The information needs of the organization and end users like you.
  • The activities, resources, and products of any present information systems.
  • The information system capabilities required meeting your information needs, and those of other end users.

a. Organizational Analysis: An organizational analysis is an important first step in system analysis. How can you improve an information system if you know very little about the organizational environment in which that system is located? You can’t. That’s why you have to know something about the organization, its management structure, its people, its business activities, the environmental systems it must deal with, and its current information systems. You must know this information in more detail for the specific end user departments that will be affected by the new or improved information system being proposed. For example, you cannot design a new inventory control system for a chain of department stores until you learn a lot about the company and the types of business activities that affect its inventory.

b. Analysis of the Present System: Before you design a new system, it is important to study the system that will be improved or replaced (if there is one). You need to analysis how this system uses hardware, software, and people resources to convert data resources, such as transaction data, into information products, such as reports and displays. Then you should document how the information system activities of input, processing, output, storage, and control are accomplished. For example, you might note the format, timing, volume, and quantity of input/output activities that provide user interface methods for interaction between end users and computers. Then, in the systems design stage, you can specify what the resources, products, and activities should be in the system you are designing.

c. Functional Requirements Analysis: This step of system analysis is one of the most difficult. You need to work with systems analysis and other end users to determine your specific information needs. For example, you need to determine what type of information you required; what its format, volume and frequency should be; and what response times are necessary. Second, you must try to determine the information processing capabilities required for each system activity (input, processing, output, storage, control) to meet these information needs. Your main goal should be to identify what should be done, not how to do it. Finally, you should try to develop functional requirements. Functional requirements are end user information requirements that are not tied to the hardware, software, and people resources that end users presently use or might use in the new system. That is left to the design stage to determine. For example, figure 4.8, outlines some of the key areas where functional requirements should be developed.

  • User interface requirements. The input/output needs of end users that must be supported by the information system, including sources, formats, content, volume, and frequency of each type of input and output.
  • Processing requirements. Activities required converting input into output. Includes calculations, decisions, decision rules, and other processing operations, and capacity, throughput, turnaround time, and response time needed for processing activities.
  • Storage requirements. Organization, content, and size of databases, types and frequency of updating and inquiries, and the length and rationale for record retention.
  • Control requirements. Accuracy, validity, safety, security, and adaptability requirements for system input, processing, output, and storage functions.

Figure 4.8 : Functional requirements specify information system capabilities required to meet the information needs of users.

3.6.3. System Design

System analysis describes what a
system should do to meet the information needs of users. System design specifies how the system will accomplish this objective. System design consists of design activities that produce system specifications satisfying the functional requirements developed in the systems analysis stage. These specifications are used as the basis for software development, hardware acquisition, system testing, and other activities of the implementation stage.

a. User Interface, Data, and Process Design: A useful way to look at system design is illustrate in figure 4.9. This concept focuses on three major products or deliverables that should result from the design stage. In this framework, systems design consists of three activities: user interface, data, and process design. This results in specifications for user interface methods and products, database structures, and processing and control procedures.

    (i) User Interface Design: The user interface design activity focuses on designing the interactions between end users and computer systems. Designers concentrate on input/output methods and the conversion of data and information between human-readable and machine-readable forms. User interface design is frequently a prototypes* process, where working models or prototypes of user interface methods are designed and modified with feedback from end users. Thus, user interface design produces detailed specifications for information products such as display screens, interactive user/computer dialogues (including the sequence or flow of dialogue), audio responses, forms, documents, and reports.

    (ii) Data Design: The data design activity focuses on the design of the structure of databases and files to be used by a proposed information system. Data design frequently produces a data dictionary, which catalogs detailed descriptions of:

  • The attributes of characteristics of the
    entities (objects, people, places, events) about which the proposed information system needs to maintain information.
  • The relationships these entities have to each other.
  • The specific data elements (databases, files, records, etc) that need to be maintained for each entity tracked by the information system.
  • The integrity rules that govern how each data element is specified and used in the information system.

    (iii) Process Design: The process design activity focuses on the design of software resources, that is, the programs and procedures needed by the proposed information system. It concentrates on developing detailed specifications for the program modules that will have to be purchased as software packages or developed by custom programming. Thus, process design produces detailed program specifications and procedures needed to meet the user interface and data design specifications that are developed. Process design must also produce specifications that meet the functional control and performance requirements developed in the analysis stage.

b. System Specifications: The design of user interface methods and products, database structures, and processing and control procedures results in hardware, software, and personnel specifications for a proposed system. Systems analysts work with you so they can use your knowledge of your own work activities and their knowledge of computer-based systems to specify the design of a new or improved information system. The final design must specify what types o hardware resources (machine and media), software resources (programs and procedures), and people resources (end user and information systems staff) will be needed. It must specify how such resources will convert data resources (store in files and databases they design) into information products (display, reports, and documents). These specifications are the final product of the systems design stage, and are called the systems specifications. Figure 4.10
outlines some of the key characteristics that should be included in system specifications.

  • User Interface specifications: The content, format, and sequence of user interface products and methods such as display screens, interactive dialogues, audio responses, forms, documents, and reports
  • Database specifications: Content, structure, distribution, and access, response, maintenance, and retention of database.
  • Software specifications: The required software package or programming specifications of the proposed system, including performance and control specifications.
  • Hardware and facilities specifications: The physical and performance characteristics of the equipment and facilities required by the proposed system.
  • Personal specifications: Job descriptions of persons who will operate the system.

Figure 4.10 : System specifications specify the details of a proposed information system.

3.6.4. Implementation and Maintenance

Once a proposed information system has been designed, it must be implemented. The systems implementation stage involves hardware and software acquisition, software development, testing of programs and procedures, development of documentation, and variety of installation activities. It also involves the education and training of end users and specialists who will operate a new system. Finally, implementation involves converting from the use of a present system to the operation of a new or improved system. This may involve operating both new and old systems in parallel for a trial period, operation of a pilot
system on a trial basis at one location, phasing
in the new system one application or location at a time, or an immediate cutover
to the new information system.

Systems maintenance involves the monitoring, evaluating, and modifying of a system to make desirable or necessary improvements. This may include a postimplementation review process to ensure that the newly implemented system meets the functional requirements established for it. Errors in the development of a system are corrected by the maintenance activity. Systems maintenance also includes making changes to tax computations in the payroll systems and tax-accounting systems of a business. However, it is vital in ensuring the success of any newly developed system because well-designed system will fail if it is not properly implemented.

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