Requirements Modeling Chapter 3 Requirements Modeling

Phase Description Systems analysis is the second of five phases in the systems development life cycle (SDLC) Uses requirements modeling and enterprise modeling to represent the new system Before proceeding to the next phase, systems design, you will consider system development strategies

Chapter Objectives Describe systems analysis phase activities and the end product of the systems analysis phase Understand joint application development (JAD) and rapid application development (RAD) Explain how systems analysts use a functional decomposition diagram (FDD) Describe the Unified Modeling Language (UML) and explain use case diagrams and sequence diagrams 3

Chapter Objectives List and describe system requirements, including outputs, inputs, processes, performance, and controls Explain the importance of scalability in system design Use fact-finding techniques, including interviews, documentation review, observation, questionnaires, sampling, and research 3

Chapter Objectives Define total cost of ownership (TCO) and explain the concept Conduct a successful interview Develop effective documentation methods to use during systems development

Introduction This chapter describes requirements modeling techniques and team-based methods that systems analysts use to visualize and document new systems The chapter then discusses system requirements and fact-finding techniques, which include interviewing, documentation review, observation, surveys and questionnaires, sampling, and research 4

Systems Analysis Phase Overview Uses models and other documentation tools to visualize and describe the proposed system The deliverable is a system requirements document Figure 3-2

Systems Analysis Phase Overview Systems Analysis Skills Analytical skills Interpersonal skills Team-Oriented Methods and Techniques Joint application development (JAD) Rapid application development (RAD)

Joint Application Development User Involvement Users have a vital stake in an information system and they should participate fully Successful systems must be user-oriented and users need to be involved

Joint Application Development JAD Participants and Roles Figure 3-4

Joint Application Development Figure 3-5

Joint Application Development JAD Advantages and Disadvantages More expensive and can be cumbersome Allows key users to participate effectively When properly used, JAD can result in a more accurate statement of system requirements, a better understanding of common goals, and a stronger commitment to the success of the new system.

Rapid Application Development Is a team-based technique that speeds up information systems development and produces a functioning information system Relies heavily on prototyping and user involvement Project team uses CASE tools to build the prototypes and create a continuous stream of documentation

Rapid Application Development RAD Phases and Activities Figure 3-7

Rapid Application Development RAD Objectives To cut development time and expense by involving the users in every phase of systems development Successful RAD team must have IT resources, skills, and management support Helps a development team design a system that requires a highly interactive or complex user interface

Rapid Application Development RAD Advantages and Disadvantages Systems can be developed more quickly with significant cost savings RAD stresses the mechanics of the system itself and does not emphasize the company’s strategic business needs Might allow less time to develop quality, consistency, and design standards

Modeling Tools and Techniques CASE Tools Figure 3-8

Modeling Tools and Techniques Functional Decomposition Diagrams A top-down representation of business functions and processes Also called structure charts

Modeling Tools and Techniques Functional Decomposition Diagrams Figure 3-9

Modeling Tools and Techniques Unified Modeling Language A widely used method of visualizing and documenting software systems design provides various graphical tools and techniques, such as use case diagrams and sequence diagrams

Modeling Tools and Techniques Unified Modeling Language Figure 3-10

Modeling Tools and Techniques Unified Modeling Language Figure 3-11

Modeling Tools and Techniques Unified Modeling Language Sequence Diagram Figure 3-13

System Requirements Checklist Five general categories Outputs Inputs Processes Performance Controls

Future Growth, Costs, and Benefits Scalability A scalable system offers a better return on the initial investment To evaluate, you need information about projected future volume for all outputs, inputs, and processes

Future Growth, Costs, and Benefits Total Cost of Ownership In addition to direct costs, systems developers must identify and document indirect expenses that contribute to the total cost of ownership (TCO) Microsoft has developed a method for measuring total costs and benefits, called Rapid Economic Justification (REJ)

Fact-Finding Overview Although software can help you to gather and analyze facts, no program actually performs fact-finding for you The first step is to identify the information you need

Fact-Finding Who, What, Where, When, How, and Why? Figure 3-15

Fact-Finding The Zachman Framework A model that asks the traditional fact-finding questions in a systems development context

Fact-Finding Figure 3-16

Interviews Systems analysts spend a great deal of time talking with people Much of that time is spent conducting interviews Consists of 7 steps

Interview Step 1: Determine the People to Interview Informal structures Step 2: Establish Objectives Determine the general areas to be discussed List the facts you want to gather

Interviews Step 3: Develop Interview Questions Creating a standard list of interview questions helps to keep you on track and avoid unnecessary tangents Avoid leading questions Open-ended questions Closed-ended questions Range-of-response questions

Interviews Step 4: Prepare for the Interview Careful preparation is essential because an important meeting and not just a casual chat Limit the interview to no more than one hour Send a list of topics Ask the interviewee to have samples available

Interviews Figure 3-18

Interviews Figure 3-19

Interviews Step 5: Conduct the Interview Develop a specific plan for the meeting Begin with good introduction Use engaged listening Allow the person enough time to think about the question Summarize main points After interview, summarize the session and seek a confirmation

Interviews Step 6: Document the Interview During the interview, note taking should be kept to a minimum After the interview, record the information quickly After the interview, send memo expressing appreciation, including the main points discussed so the interviewee has a written summary and can offer additions or corrections

Interviews Step 7: Evaluate the Interview In addition to recording the facts obtained in an interview, try to identify any possible biases Unsuccessful Interviews No matter how well you prepare for interviews, some are not successful

Other Fact-Finding Techniques Document Review Observation Seeing the system in action gives you additional perspective and a better understanding of the system procedures Plan you observations in advance Hawthorne Effect

Other Fact-Finding Techniques Questionnaires and Surveys Keep the questionnaire brief and user-friendly Provide clear instructions that will answer all anticipated questions Arrange the questions in a logical order, going from simple to more complex topics

Other Fact-Finding Techniques Questionnaires and Surveys Phrase questions to avoid misunderstandings; use simple terms and wording Try not to lead the response or use questions that give clues to expected answers Limit the use of open-ended questions that are difficult to tabulate

Other Fact-Finding Techniques Questionnaires and Surveys Limit the use of questions that can raise concerns about job security or other negative issues Include a section at the end of the questionnaire for general comments Test the questionnaire whenever possible on a small test group before finalizing it and distributing to a large group

Other Fact-Finding Techniques Sampling Systematic sample Stratified sample Random sample Main objective of a sample is to ensure that it represents the overall population accurately

Other Fact-Finding Techniques Research Newsgroups Site visit Figure 3-23

Other Fact-Finding Techniques Interviews versus Questionnaires When you seek input from a large group questionnaire is a very useful tool If you require detailed information from only a few people, then you probably should interview each person Interview is more familiar and personal Questionnaire gives many people the opportunity to provide input and suggestions

Documentation The Need for Recording the Facts Record information as soon as you obtain it Use the simplest recording method Record your findings in such a way that they can be understood by someone else Organize your documentation

Documentation Software Tools CASE tools Word processing Spreadsheets Databases Figure 3-24

Documentation Software Tools Presentation graphics Personal information managers

Preview of Enterprise Modeling At the conclusion of requirements modeling, systems developers should have clear understanding of business processes and system requirements The next step is to model the logical design of the system

Chapter Summary The systems analysis phase includes three activities The main objective is to understand the proposed project and build a solid foundation for the systems design phase The fact-finding process includes interviewing, document review, observation, questionnaires, sampling, and research. 49

Chapter Summary Systems analysts should carefully record and document factual information as it is collected, and various software tools can help an analyst visualize and describe an information system Chapter 3 Complete 49