Contemporary Information Systems Development

Chapter 10

Chapter Objectives

• Explain emerging approaches for collecting and structuring the information needed to design and construct an information system

• Describe prototyping, rapid application development, and object-oriented analysis and design

• Understand how and why to use several automated tools for supporting contemporary development

Contemporary Methods for Collecting and Structuring

System Requirements

• Critical Success Factors (CSF)

• Joint Application Requirements (JAR)/Joint Application Design (JAD)

Critical Success Factors (CSF)

• Something that must go well to ensure success for a manager, department or company

• How the CSF approach works– Select people from a cross-section of the major

functional areas– Ask each person to define his or her own CSF– Merge personal CSF to create set of organization-

wide CSF

Merging Individual CSF to Organizational CSF

Strengths and Weaknesses of the CSF Approach

• Strengths– Understandable by

senior managers– Provides structured

process for collecting information needs of company

• Weaknesses– Can lead to an over-

simplification of a complex situation

– Hard to find analysts to perform the CSF process

– Not user-centered

Joint Application Requirements (JAR)Joint Application Design (JAD)

• Group-based methods for collecting requirements and creating designs

• How the JAD approach works– Held in a conference room or a special-

purpose JAD room– JAD expert facilitator helps group work

effectively– Scribe records jointly agreed-upon design

information

JAD Room

Strengths and Weaknesses of JAD

• Strengths– More people

involved in the effort– Provides greater

acceptance of new system

– Training and support costs significantly lower

• Weaknesses– Difficult to get all

relevant users together

– Inherent group process problems

Contemporary Approaches for Designing and Building Systems

• Prototyping

• Rapid Application Development

• Object-Oriented Analysis and Design

Prototyping

• Uses a “trial-and-error” approach• How Prototyping Works

– Interview users of the system– Develop a prototype of the new system– Share with users – Users preview and ask for changes– Modify the prototype again; share with users– Continue process until users approve the system

The PrototypingProcess

Strengths and Weaknesses of Prototyping

• Strengths– Develops close

working relationship between designer and users

– Best method for systems with hard-to-define specifications

– Works well with other development tools

• Weaknesses– Not appropriate for

every type of system– Sometimes rushes

the development process

Rapid Application Development (RAD)

• How RAD works– Prototyping– Computer-based

development tools– Special management

practices– Close user

involvement

• Four-phased methodology– Requirements

planning– User design– Construction– Move to the new

system

Iterative Refinement of RAD

Strengths and Weaknesses of Rapid Application Development• Strengths

– Has active involvement of users

– Produces a system in a fraction of the time normally needed

• Weaknesses– Can limit systems in

functionality and flexibility for change

– May not be of highest quality

Object-Oriented Analysis and Design (OOA&D)

• Uses object-oriented languages (OOP) with reusable modules

• How OOA&D works– Requirements broken down into smaller and

smaller pieces called “modules”– Modules defined, programmed, and then

pieced together to create the system– Has a tight coupling between data and the

operations performed on them

Strengths and Weaknesses of OOA&D

• Strengths– Forces designers to

integrate their thinking

– Can improve quality – Can reduce

development time– Objects can be

reused by other systems

• Weaknesses– Needs retraining of

existing analysts and programmers

– No research to support claim of higher quality or reduced time

– Many programmers do not search for reusable code

Tools for Supporting Contemporary Systems

Development

• Computer Aided Software Engineering (CASE)

• Group Support Systems

• Advanced Programming Languages

Computer Aided Software Engineering (CASE)

• Automated software tools used to develop information systems

• Upper CASE – Used to automate the first three phases of

SDLC

• Lower CASE – Used to automate the last two phases of

SDLC

High-level DFD

Lower-level DFD

General Types of CASE Tools

• Diagramming tools

• Screen and report generators

• Analysis tools

• Repository

• Documentation generators

• Code generators

Group Support Systems

• GSS technology used to structure and coordinate group processes

• GSS + JAD = Electronic JAD (E-JAD)– Using GSS software to support JAR / JAD

activities

Advanced Programming Languages

• Visual Programming– Allows developers to quickly build new user

interfaces, reports, and other features

• Object Oriented Programming (OOP)– Creates reusable objects

• Fourth-Generation Languages and Beyond– Allows users to request information with easy to

use syntax