Requirements Modeling

Requirements Modeling

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

Systems Analysis Phase Overview • The overall objective is to understand the proposed project, ensure that it will support business requirements, and build a solid foundation for system development • You use models and other documentation tools to visualize and describe the proposed system

Systems Analysis Phase Overview • Systems Analysis Activities • Requirements modeling • Outputs • Inputs • Processes • Performance • Security • Data and process modeling

Systems Analysis Phase Overview • Systems Analysis Activities • Development Strategies • System requirements document

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

Fact-Finding • Fact-Finding Overview • The first step is to identify the information you need • Who, What, Where, When, How, and Why? • Difference between asking what is being done and what could or should be done

Performing Requirements Determination • Gather information on what system should do from many sources • Users • Reports • Forms • Procedures

Performing Requirements Determination • Characteristics for gathering requirements • Question everything • Impartiality • Find the best organizational solution • Relaxation of constraints • Attention to detail • Reframing • View the organization in new ways

Deliverables and Outcomes • Types of deliverables: • Information collected from users • Existing documents and files • Computer-based information • Understanding of organizational components • Business objective • Information needs • Rules of data processing • Key events

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

Traditional Methods for Determining Requirements • Interviewing and Listening • Gather facts, opinions and speculations • Observe body language and emotions • Guidelines • Plan • Checklist • Appointment • Be neutral • Listen • Seek a diverse view

Traditional Methods for Determining Requirements • Interviewing (Continued) • Interview Questions • Open-Ended • No pre-specified answers • Close-Ended • Respondent is asked to choose from a set of specified responses • Additional Guidelines • Do not phrase questions in ways that imply a wrong or right answer • Listen very carefully to what is being said • Type up notes within 48 hours • Do not set expectations about the new system

Interview • Step 1: Determine the People to Interview • Informal structure • Step 2: Establish Objectives for the Interview • 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 interview is 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 • Step 5: Conduct the Interview • Develop a specific plan for the meeting • Begin by introducing yourself, describing the project, and explaining interview objectives • 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

CASE IN POINT 3.2: Deep River College Deep River College is a two-year school in Southern California. Twice a year, the fund-raising office at Deep River mails requests for donations to the alumni. The staff uses a word processing program and a personal information database to create personalized letters., Data on past contributions and other alumni information, however, is stored manually. The dean, Alexandra Ali, recently submitted a systems request asking the college’s IT department to develop a computerized alumni information system. The school does not have a formal systems review committee, and each department has an individual budget for information services. Eddie Bateman, a systems analyst, performed a preliminary investigation and he concluded that the system met all the feasibility tests. After reading his report, Alexandra asked him to proceed with the systems analysis phase. Eddie has scheduled an interview with her, and he asked you to help him prepare for the meeting. Specifically, he wants you to list all the topics he should cover during the interview. Eddie also wants you to prepare a list of specific questions that he should ask. Be sure to include open-ended, closed-ended, and range-of-response questions.

CASE IN POINT 3.3: FastPak Overnight Package System • FastPak, the nation’s fourth-largest overnight package system, is headquartered in Los Angeles, California. Jesse Evans is a systems analyst on an IT team that is studying ways to update FastPak’s package tracking system. Jesse prepared well for her interview with Jason Tanya, FastPak’s executive vice president. Mr. Tanya did not ask his assistant to hold his calls during the meeting, however. After several interruptions, Jesse tactfully suggested that she could come back another time, or perhaps that Mr. Tanya might ask his assistant to hold his calls. “No way,” he replied. “I’m a very busy man and we’ll just have to fit this in as we can, even if it takes all day.” Jesse was unprepared for his response. What are her options? Is an analyst always in control of this kind of situation? Why or why not?

Traditional Methods for Determining Requirements • Administering Questionnaires • More cost-effective than interviews • Choosing respondents • Should be representative of all users • Types of samples • Convenient • Random sample • Purposeful sample • Stratified sample

Traditional Methods for Determining Requirements • Questionnaires • Design • Mostly closed-ended questions • Can be administered over the phone or in person • Vs. Interviews • Interviews cost more but yield more information • Questionnaires are more cost-effective

Traditional Methods for Determining Requirements • Interviewing Groups • Advantages • More effective use of time • Enables people to hear opinions of others and to agree or disagree • Disadvantages • Difficulty in scheduling • Nominal Group Technique • Facilitated process to support idea generation by groups • Individuals work alone to generate ideas which are pooled under guidance of a trained facilitator

Traditional Methods for Determining Requirements • Directly Observing Users • Serves as a good method to supplement interviews • Often difficult to obtain unbiased data • Hawthorne Effect • People often work differently when being observed

Analyzing Procedures and Other Documents • Types of information to be discovered: • Problems with existing system • Opportunity to meet new need • Organizational direction • Names of key individuals • Values of organization • Special information processing circumstances • Reasons for current system design • Rules for processing data

Analyzing Procedures and Other Documents • Four types of useful documents • Written work procedures • Describes how a job is performed • Includes data and information used and created in the process of performing the job or task • Business form • Explicitly indicate data flow in or out of a system • Report • Enables the analyst to work backwards from the report to the data that generated it • Description of current information system

Modeling Tools and Techniques • CASE Tools • Offer powerful modeling features • Systems analysts use modeling and fact-finding interactively • Functional Decomposition Diagrams • Functional decomposition diagram (FDD)

Modeling Tools and Techniques • Unified Modeling Language • Provides various graphical tools • Use case diagrams • Actor • Sequence diagrams

What is UML? • UML stands for Unified Modeling Language • The UML is the standard language for visualizing, specifying, constructing, and documenting the artifacts of a software-intensive system • It can be used with all processes, throughout the development life cycle, and across different implementation technologies

Modern Methods for Determining Requirements • Joint Application Design (JAD) • Brings together key users, managers and systems analysts • Purpose: collect system requirements simultaneously from key people • Conducted off-site • Prototyping • Repetitive process • Rudimentary version of system is built • Replaces or augments SDLC • Goal: to develop concrete specifications for ultimate system

CASE IN POINT 3.1: North Hills Consulting Suppose you were employed as a summer intern by North Hills Consulting, which offers a wide range of IT services to clients. North Hills has a Web site that describes the firm and the services it offers. The site includes a monthly feature called “Hot Topic,” which reviews current IT trends and developments. Yesterday, Jane Hall, your supervisor, mentioned that next month’s topic would be JAD and RAD, and she asked you to write a draft of the Hot Topic article. Specifically, she wants you to go online and locate at least three references that would be of interest to readers who want to learn more about JAD or RAD. When you have completed your research, she wants you to write a summary of your findings. http://www.credata.com/research/methodology.html

Joint Application Design (JAD) • Participants • Session Leader • Users • Managers • Sponsor • Systems Analysts • Scribe • IS Staff

Joint Application Design (JAD) • End Result • Documentation detailing existing system • Features of proposed system • CASE Tools During JAD • Upper CASE tools are used • Enables analysts to enter system models directly into CASE during the JAD session • Screen designs and prototyping can be done during JAD and shown to users

Joint Application Design (JAD) • Supporting JAD with GSS • Group support systems (GSS) can be used to enable more participation by group members in JAD • Members type their answers into the computer • All members of the group see what other members have been typing

Joint Application Development • JAD Advantages and Disadvantages • Advantages • 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 • Disadvantages • More expensive and can be cumbersome if the group is too large relative to the size of the project

Prototyping • Quickly converts requirements to working version of system • Once the user sees requirements converted to system, will ask for modifications or will generate additional requests • Most useful when: • User requests are not clear • Few users are involved in the system • Designs are complex and require concrete form • History of communication problems between analysts and users • Tools are readily available to build prototype

Prototyping • Drawbacks • Tendency to avoid formal documentation • Difficult to adapt to more general user audience • Sharing data with other systems is often not considered • Systems Development Life Cycle (SDLC) checks are often bypassed

System Requirements Checklist • Five general categories • Outputs • Inputs • Processes • Performance • Controls

System Requirements Checklist • Outputs • The Web site must report online volume statistics every four hours, and hourly during peak periods • The inventory system must produce a daily report showing the part number, description, quantity on hand, quantity allocated, quantity available, and unit cost of all parts — sorted by part number

System Requirements Checklist • Inputs • Manufacturing employees must swipe their ID cards into online data collection terminals that record labor costs and calculate production efficiency • The department head must enter overtime hours on a separate screen

System Requirements Checklist • Processes • The student records system must calculate the GPA at the end of each semester • As the final step in year-end processing, the payroll system must update employee salaries, bonuses, and benefits and produce tax data required by the IRS

System Requirements Checklist • Performance • The system must support 25 users online simultaneously • Response time must not exceed four seconds

System Requirements Checklist • Controls • The system must provide log-on security at the operating system level and at the application level • An employee record must be added, changed, or deleted only by a member of the human resources department

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 • Total cost of ownership (TCO) is especially important if the development team is evaluating several alternatives • One problem is that cost estimates tend to understate indirect costs • Rapid Economic Justification (REJ)

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 • Productivity Software • Word processing, spreadsheets, database management, presentation graphics, histogram

Documentation • Software Tools • Graphics modeling software • Personal information managers • Personal information manager (PIM) • Handheld computers • Personal digital assistants (PDAs) • Wireless communication devices

Preview of Data and Process Modeling • At the conclusion of requirements modeling, systems developers should have clear understanding of business processes and system requirements • The next step is to construct a logical design of the system • The systems analysis phase includes three activities: requirements modeling, data and process modeling, and consideration of development strategies

Requirements Modeling