sylnovie merchant, ph.d. mis 210 fall 2004 lecture 2: sdlc methodologies project initiation and...

Sylnovie Merchant, Ph.D. MIS 210 Fall 2004

Lecture 2:SDLC

MethodologiesProject Initiation and Planning

Requirements Analysis

MIS 210Information Systems I


Systems DevelopmentLife Cycle

(SDLC)


Systems Development

What is a system?A collection of related components that interact to perform a task in order to accomplish a goal

Systems development (systems analysis and design) is the process of creating systems, developing them, and maintaining or enhancing them.


Characteristics of Software

• Software is developed, not manufactured

• Software does not “wear out”– although it can become obsolete


Today’s Software Development Environment

• Failures

• Productivity gap

• Backlogs

• Maintenance bound


Alleviating the Problems in Systems Development

Elimination of the causes of system failure lie in

1. the application of methodologies

2. modeling tools

3. techniques

4. project management techniques

to design and build IS that not only meet the needs of the

users, but also are delivered on time and within budget


Principles of Successful Systems Development

• Get the user involved

• Use a problem-solving approach

• Establish phases and activities

• Establish standards for development and documentation

• Justify systems as capital investments

• Don't be afraid to cancel or revise scope

• Divide and conquer

• Design systems for growth and change

• Proper planning and project management


Some Key Terms ...• Systems development life cycle (SDLC): the life of a project, from

concept through implementation

• Methodology: a comprehensive and detailed version of an entire SDLC

• Technique: an approach that applies specific tools and rules to complete one or more phases of the methodology

• Modeling tools: specific tools used to apply techniques

• Project management techniques: tools used to help plan, schedule, and control a project


Tools

• Software support that helps create models or other project components

• From simple drawing programs to complex CASE tools


Some Tools

• Project management applications• Drawing/graphics applications• Word processing/text editor• Computer-aided system engineering (CASE) tools• Integrated development environment (IDF)• Database management applications• Reverse-engineering tool• Code generators


Techniques

• Collection of guidelines that help the analyst complete a system development activity or task

• Step-by-step instructions• General advice


Some Techniques

• Strategic planning• Project management• User interviewing• Data-modeling• Relational database design


Systems Development Lifecycle (SDLC)

• Three major activities– Analysis: understanding business needs– Design: conceptualizing computer-system

solution– Implementation: construction, testing, and

installation

• Two additional phases– Project planning– Support


The SDLC

1. Planning

a. Project identification and selection

b. Project initiation and planning

2. Analysis

a. Determine system requirements (WHAT users need)

b. Modeling possible solutions (HOW to satisfy user needs)

3. Design

a. logical design

b. physical design

4. Implementation

5. Maintenance / support

Frontend

Backend

A

D

I


SDLC Concepts

• All projects use some variation of the SDLC

• SDLC is more than phases

– Principles of management

– Planning and control

– Organization and scheduling

– Problem solving


Major Attributes of the Life Cycle

• The project --– Moves systematically through phases where

each phase has a standard set of outputs– Produces project deliverables– Uses deliverables in implementation– Results in actual information system– Uses gradual refinement


Project Phases

• Planning (Why build the system? How should the team go about building it?)

• Analysis (Who uses system, what will it do, where and when will the system be used?)

• Design (How will the system work?)

• Implementation (System delivery)


• Identifying business value

• Analyze feasibility

• Develop work plan

• Staff the project

• Control and direct project

Planning


• Design selection

• Architecture design

• Interface design

• Data storage design

• Program design

Design


• Construction– Program building– Program and system testing

• Installation– Conversion strategy– Training plan– Support plan

Implementation


Support Phase• Objective: Keep system running productively

following initial installation– End-user support

• Help desks• Training programs

– Maintaining and enhancing computer system• Enhancements• Upgrades• Maintenance


Methodologies


Common Development Methodologies and Techniques

Code & fix model Structured development Prototyping Rapid application development Object-oriented development


Code and Fix It Model

• An early technique

• The developer, in the following order:– codes– thinks about requirements– fixes the code– continues this process until...


Structured Development

• Based on the principles of:– modularization

– top-down decomposition

– process driven

• Structured programming• Structured design• Structured analysis


Systems Development Life CycleWaterfall Model

Project Identification and Selection

Project Initiationand Planning

Analysis

Logical Design

Physical Design

Implementation

Maintenance


Waterfall Model

• Problems– dependent on documents, particularly in

completing the requirements and design phases– tendency to hide poorly understood requirements

with elaborate specifications


Advantages of Structured Development

• Been used successfully for over 30 years

• Provides a clear framework that defines and divides important activities

• Can be applied to both small and large projects

• Division of labor is easier to facilitate


Limitations of Structured Development

• Specification problems– assumes that development is a sequential

process• Changing requirements

– requirements specified at the beginning– assumption that requirements will not change

• Conceptualization and visualization– document led methodology– volume of documentation can be huge

• Inaccuracy– there is only downward trend


Prototyping

• Principle: a user can tell you better what they DON'T want than what they DO want

• Expendable (throw-away) prototyping:– discarded after use– used to support the analysis and design phases

• Evolutionary prototyping:– prototype evolves into the final system– is it a methodology?


Advantages• Speed

• Easier for end-users to learn

• System changes discovered earlier

• End-user involvement (ownership)– increased user satisfaction

– increased user acceptance

• User-analyst communication

• Early problem detection– reduced development time

– reduced maintenance


Disadvantages

• Poor documentation

• Hard to control/manage

• (Unrealistic) User expectations– time for final system– final system differences

• reduced analysis


Rapid Application Development(RAD)

• Logistical approach to systems design• Combines

– integrated CASE tools– information engineering methodologies– management techniques

• Speeds up Systems Development by as much as 20 times

• Critics consider it incomplete life cycle


Object-Oriented (OO) Development

• A fundamentally new way of thinking about developing systems

• Object-oriented: means that we organize software as a collection of discrete objects that incorporate both data and behavior

• Object-oriented development: an approach to systems development that proposes the use of objects in the building of new systems and the rebuilding of old ones


Reus

e

Advantages of OO

• Faster development

• Higher quality

• Easier maintenance

• Increased scalability

• Better information structure

• Increased adaptability

• Increased modeling power

• Supports complexity


Disadvantages of OO

• Maturity of technology

• Need for standards

• Lack of database technology

• Lack of reusable software

• Lack of metrics

• Speed of execution

• Availability of qualified personnel

• Cost of conversion


Project Initiation and Planning


Project Initiation and Planning• Long-term information systems strategic plan (top-

down)

• Department managers or process managers (bottom-up)

• Response to outside forces– Legislative changes– Market forces– Competition


Confirming Project Feasibility

• Economic• Organizational and cultural• Technological• Schedule• Resource


Intangibles in Economic Feasibility

• Costs and benefits cannot always be measured• Examples

– Increased levels of service– Survival– Lost customers or sales


Organizational and Cultural Feasibility

• Each company has own culture

• New system must fit into culture

• Evaluate related issues for potential risks


Technological Feasibility

• Does system stretch state-of-the-art?

• Does expertise exist in-house for development?

• Does a third party need to be involved?


Schedule Feasibility

• Can project be completed on time?

• Risk of schedule slipping

• Assumptions and estimates


Resource Feasibility• Team member availability

• Team skill levels

• Equipment

• Support staff

• Physical facilities


Developing Project Schedule

• Task: smallest piece of work• Activity: group of tasks• Phase: group of activities• Schedule process

– List all tasks for each SDLC activity– Estimate sizes of each task– Determine task sequence– Schedule tasks


Project Staffing• Develop resource plan for the project

• Identify and request specific technical staff

• Identify and request specific user staff

• Organize the project team into work groups

• Conduct preliminary training and team building exercises


Launching Project

• Oversight committee is finalized and meets to give go-ahead

• Formal announcement made

• Key question, “Are we ready to start?”


Focusing the Investigation

• Most system problems occur in complex tasks that have high user impact

• Application complexity

• User impact


Requirements Analysis


Analysis

A. Determine system requirements

B. Structure requirements– 1. Process modeling– 2. Logic modeling– 3. Data modeling

C. Select best alternative


Requirements Analysis Goals

• Fully describe the current system– Study and analyze the current system (gather

and study facts)

• Determine the ideal information system

• Identify resource constraints

• Define and prioritize requirements

• Inspire user confidence/ownership


Study & Analyze Current System

• Gather information on what the system should do from as many sources as possible

• Concentrate on WHAT is needed, not HOW to do it

• “Don’t try to fix it unless you understand it”

• Major problem: analyst not understanding user needs



-- Activities --

1. Learn about current system (gather facts)

2. Model current system

3. Analyze problems/opportunities (study facts)

4. Establish new system objectives



-- Output --1. Complete statement of user environment

2. Models of current system

3. List of major problems/causes/effects

4. System objectives


Learn About Current System (gather facts)

Gather information from:– Current information system:

• a current IS may exist

– External sources: • reviewing other IS outside the organization can

reveal practical ideas and techniques

– Internal sources:• single most important source of facts is the

user• existing paper work or documents is also a

good source


Tactics

• Listen - don’t lecture• Don’t pre-solve problem• Compare stories • Look for reluctant responses• Observe your effects on system• Avoid politics (head nodding)• Expect hard, boring work


Fact-finding Methods

• Research and site visits

• Existing documentation

• Observation

• Questionnaires

• Interviews


Observation

• Not for long periods of time– will change what your measuring

• Vary observation periods• Take only minimal, preplanned notes• Coordinate visit beforehand• Beware of Selective Perception!!!


Questionnaires-- Types --

• Open-ended (free format)

• Closed-ended (fixed format)– multiple choice– rating– ranking– single fact


Questionnaire Development

1. Determine what facts need to be collected

2. Determine whether free- or fixed-format is best. Usually, a

combination is used.

3. Write the questions. Examine them carefully. Make sure

the questions don't reflect your personal biases.

4. Test the questions on a small sample of respondents.

Modify those questions that respondents had problems with.

5. Duplicate and distribute the questionnaire.


Questionnaires - the Good and the Bad

Advantages– Can be quickly answered.– Cheap for gathering data from a large number of users.– Allow users to maintain anonymity.– Responses can be tabulated and analyzed quickly.

Disadvantages– Number of respondents is often low.– No guarantee that the user will answer all the questions.– Inflexible - voluntary information is stifled.– Elimination of body cues.– No immediate opportunity to clarify an answer.– Good questionnaires are difficult to prepare.


Interviews

• Types of Interviews1. Unstructured2. Structured

• Types of Questions1. Open-ended2. Closed-ended

• Focus of Questions1. Decision analysis2. Data analysis


How to Conduct an Interview

1. Select interviewees. Learn as much as you can about interviewee.

2. Make an appointment - never 'drop by'

3. Limit the interview to between 1/2 hour and 1 hour

4. Clear it with the interviewee's supervisor

5. Conduct the interview in a private location

6. Prepare for the interview: provide an interview agenda

7. Conduct the interview: opening, body, conclusion

8. Follow-up


Interviewing Tips

• Watch the time

• Don’t look at watch

• No leading questions

• Listen

• No body language


• Make the user feel important

• Be courteous and professional

• Don’t take exhaustive notes

• Use structured questions

• Don’t ask users to remember details

• Avoid gang interviews

More Interviewing Tips


Interviews - the Good and the Bad

• Advantages– Users are actively involved– SA can probe for more feedback from user– SA can reword questions for each interviewee– Body cues

• Disadvantages– Very time consuming, thus very costly– Success of the interview is dependent on the SA's human

relations skills– Interviewing may be impractical due to location of

interviewees


Overall Strategy for Fact Finding

1. Learn all you can from existing documents

2. If appropriate, observe the system in action

3. Conduct interviews

4. Use questionnaires to clear up things you don't

fully understand

5. Follow-up


Some Questions That Must be Answered

• What are the inputs to this system?

• What are the outputs of this system?

• What is the business process (i.e., how is data processed)?

• Who are the direct end-users?

• How will the users feel about this system?

• Who developed the existing system?


Analyze Problems / Opportunities(study facts)

• Study and analyze the "current" system• Problem analysis is difficult.

– We often try to solve problems without analyzing them.– We try to state the problem in terms of a solution.

• Use the PIECES framework to frame your investigation of the problems, opportunities, and requirements– Performance analysis– Information and data analysis– Economic analysis– Control and security analysis– Efficiency analysis– Service analysis


Requirements Analysis Document

• Parts– How analysis was conducted

• credibility

• restarts

– User requirements– System constraints– Realistic System Objectives– Documentation


User Requirements

• User system objectives (unedited)

• Reports (type/frequency)

• User training needs

• Effect of system on various users– Organization Chart

sylnovie merchant, ph.d. mis 210 fall 2004 lecture 2: sdlc methodologies project initiation and...

Documents

sylnovie merchant

project slide

project management slide

design systems

case tools slide

budget slide

obsolete slide

information systems