1. The Information Systems Development Processes Chapter 9

2. Chapter Objectives Understand the process used by organizations to manage the development of IS Describe each major phase of the system’s development life cycle Explain how organizations identify projects, assess feasibility, identify benefits and costs, and perform economic analysis of a system project

3. The Need for Structured Systems Development Systems Development –Process of designing, building and maintaining information systems Performed by systems analysts –Requires both managerial and technical expertise

4. The Evolution of Information Systems Development Early days –Techniques used to develop systems varied –Difficult to integrate large systems In response, IS professionals developed software engineering –Easier to train programmers and analysts to use common techniques –Results in more maintainable systems

5. Options for Obtaining Information Systems Build internally by IS staff Buy a pre-packaged system Hire an organization or consultant to custom-build a system –Outsourced Users/departments build their own custom systems for their individual needs –End-user development

6. Sources for IS

7. Information Systems Development in Action The problem decomposition process

8. The Role of Users in the Systems Development Process Systems analysts rely on information from system users Key to project success –A close and mutually respectful working relationship between analysts and users

9. Steps in the Systems Development Process System identification, selection, and planning System analysis System design System implementation System maintenance

10. Phase 1: System Identification, Selection, and Planning Undertake only those projects critical to mission, goals, and objectives Select a development project from all possible projects that could be performed Different evaluation criteria used to rank potential projects

11. Assessing Project Feasibility Economic Technical Operational Schedule Legal and contractual Political

12. Identifying System Benefits Tangible benefits easily measured in dollars and certainty –Reduced personnel expenses –Lower transaction costs –Higher profit margins Intangible benefits difficult to measure –Improvement of employee morale –Reduction of waste creation

13. Identifying System Costs Tangible costs –Hardware –Labor –Employee training Intangible costs –Loss of customer goodwill –Loss of employee morale

14. Performing an Economic Analysis of a System Project Uses the concept of the time value of money –Compare present cash outlays to future expected returns Spreadsheet analysis –Net present value –Return on investment –Break-even analysis

15. Phase 2: System Analysis Gain a thorough understanding of an organization’s current way of doing things Determine system requirements –Interview users –Develop questionnaires –Watch the day-to-day activities of users Organize information using data, process, and logic-modeling tools

16. Modeling Organizational Data Systems analysts determine data needed to accomplish intended tasks Use data-modeling tools to depict the data Entity-Relationship Diagram –Relationships represented on diagram by lines drawn between entities

17. Entity-Relationship Diagram

18. Modeling Organizational Processes Data flows –Show the movement of data within an information system Processing logic –Represents the way data are transformed

19. Phase 3: System Design The proposed system is designed Elements designed include –Forms and reports –Interfaces and dialogs –Databases and files –Processing and logic

20. Designing Forms and Reports Forms –Collect data to input into system –Some pre-defined data with blank spaces for additional data Reports –Receive information from system –Static documents that summarize data

21. Designing Interfaces and Dialogs Text-based interfaces –Waits for a text command from the user Graphical user interfaces (GUI) –Provides user with icons and menus of choices –First introduced on Macintosh –Windows made GUI available to IBM- based machines

22. Designing Databases and Files Requires thorough understanding of the data and informational needs Uses data-modeling tools to create a conceptual data model

23. Designing Processing and Logic Steps and procedures that transform data into new or modified information Pseudo code –Text descriptions of detailed processing steps Structure charts –Break a large problems into smaller pieces Decision trees –Help design how the logic flows

24. Structure Chart

25. Decision Tree

26. Phase 4: System Implementation Transform the design into a working system –Software programming –Testing Prepare organization to use the new system –System conversion –Documentation –User training –Support

27. Software Programming and Testing Programming –Transforming the system design into a working computer system Testing –Developmental testing by programmers to assure that each module is error-free –Alpha testing by software testers to assess if it meets the design requirements of the users –Beta testing by actual system users to test with actual data

28. System Conversion, Documentation, Training and Support Conversion –Parallel conversion –Direct conversion –Phased conversion –Pilot conversion Documentation –User guides –User training –Installation procedures Training –In-house –Outside vendors Support –Install system –Consult on features –Set up user accounts –Provide demonstrations –Help with problems

29. Software Conversion Strategies

30. Phase 5: System Maintenance Largest part of system development effort Maintenance process –Obtain maintenance request –Transform requests into changes –Design changes –Implement changes

31. Changing Maintenance Mix

32. Types of Maintenance Corrective –To repair flaws in the design, coding, or implementation Adaptive –To meet changing business needs Perfective –To improve processing performance Preventive –To reduce the chance of future system failure