CIS 321—IS Analysis & Design

Chapter 4: Analysis—Investigating System

Requirements

2

Overview A reminder—the ______ consists of five phases:

Planning Analysis Design Implementation Maintenance

Two key activities (skills) involved with analysis: Investigate the system requirements* Model the business processes to meet the

requirements** Investigation

Become an expert about the current/proposed system*Covered in this chapter **Covered in Chapter 5

3

Activities of the Analysis Phase

Gather information Define system requirements Prioritize system requirements Prototype for feasibility and __________ Generate and evaluate alternatives Review recommendations with management

4

Gather (All) Information About the existing business

process/information system Interview users/stakeholders Observe users Become deeply involved

About the proposed business process/information system Interview users of similar systems

About the technical issues of the existing/proposed system ___________ with other systems Software packages that may meet requirements

5

Define System Requirements

Types of requirements Functional—what functions need to be performed __________—how to perform the required functions

Two types of models Detailed logical

Performed during analysis, w/o reference to technology Detailed __________

Performed during design, w/ reference to technology

How to model Create, refine, cross-validate with other models Specific models depend on development

methodology

6

Prioritize Requirements Categorize system functions

Essential Desirable

Resources are limited Each requirement must be justified

Without prioritization, scope _______ can occur

7

Prototype Two reasons for prototyping in the analysis

phase Verify the plan can meet existing requirements

Problem domain (user view) Technology domain (system view)

___________ new requirements Problem domain (user view) Technology domain (system view)

8

Generate and Evaluate Alternatives

Possible alternatives for system development In-house development Third party development Packaged software

Also known as make vs. _____

9

Review Recommendations w/ Management

Keep management informed throughout the analysis phase

Decisions Should the project continue? (go-no go) If so, which alternative should be selected?

What is the revised budget and schedule?

10

Business Process Reengineering

Different philosophies about change If it ain’t broke, don’t fix it _____________ improvement (many small improvements) BPR (major changes)

Customer ____________ management (CRM) Keep detailed information about customers to serve

them better What if BPR costs jobs?

If your company doesn’t make major improvements, your competitors will and you will go out of business entirely

If possible, go beyond the obvious requirements

11

System Requirements Definition

All of the capabilities and constraints that the new system must meet

Two types of system requirements Functional (functions the system must perform) Nonfunctional (how the system must function)

Technical (What operating system? Wireless network?) Performance (Response time? Number of users?) Usability (Types of menus? Legal disclaimers?) Reliability (Required uptime? Procedures for downtime?) Security (Who has access?)

12

Stakeholders—The Source Definition

Those who have an interest in the successful implementation of the system

All stakeholders must be included in analysis Types of stakeholders

Users Horizontal—across departments Vertical—business, information, management, executive,

external _______

Person or group providing the funding for the project Technical staff

Can the technical staff support the technical requirements?

13

Old vs. New Systems In the past…

the existing system was completely documented before the new system was studied

Today… the analyst begins with the new system

requirements (to save time) the existing system is studied only to discover

business needs

14

Themes for Questions The goal: build a _______ model of the new

system Three major questions must be answered in

detail What are the business processes? How is the business process performed? What information is required?

Be effective and efficient in your analysis

15

Information Gathering Methods

Review existing documentation (external / internal) Conduct interviews with users (checklist, p. 130)

prepare, conduct, follow up Observe and document business processes

use activity diagrams (part of UML) to document workflow Build prototypes

desired characteristics: operative, focused, quick Distribute and collect questionnaires (limited use) Conduct JAD or GSS sessions Research vendor solutions (but be careful)

16

Validating Requirements Developing a system is like constructing a

building Structured walkthrough—a review of all the

findings during analysis What and when? All the models developed Who? Developers and stakeholders How?

preparation execution follow-up