SYSTEM ANALYSIS - SYSTEM DEVELOPMENT TOOLS

SYSTEM DEVELOPMENT TOOLS

SYSTEM ANALYSIS - SYSTEM DEVELOPMENT TOOLS

Data Collection tools

·         Also known as “requirements-gathering/determining techniques”

·         Gather information on what system should do from many sources

o   Users

o   Reports

o   Forms

o   Procedures

 

Characteristics for gathering requirements

·         Impertinence: Question everything

·         Impartiality: Find the best solution of the organisation

·         Relaxation of constraints

·         Attention to detail

·         Reframing: View the organisation in new ways

 

Types of deliverables

·         Information collected from users

·         Existing documents and files

·         Computer-based information

·         Understanding of organisational components

o   Business objectives

o   Information needs

o   Rules of data processing

o   Key events

 

Tools divided into two:

- Traditional

- Modern

 

Traditional tools

Interviewing and Listening

·         Most commonly used methods

·         Gather facts, opinions and speculations

·         Observe body language and emotions 

 

Basic steps:

·         Selecting Interviewees

·         Designing Interview Questions

·         Preparing for the Interview

·         Conducting the Interview

·         Post-Interview Follow-up

 

Selecting Interviewees

·         Based on information needs

·         Best to get different perspectives

o   Managers

o   Users

o   Ideally, all key stakeholders

·         Keep organizational politics in mind

 

Designing interview questions

Unstructured interview useful in early information gathering

·         Goal is broad, roughly defined information

Structured interview useful later in process

·         Goal is very specific information

 

Preparing for the interview

Prepare general interview plan

·         List of question

·         Anticipated answers and follow-ups

Confirm areas of knowledge

Set priorities in case of time shortage

Prepare the interviewee

·         Schedule

·         Inform of reason for interview

·         Inform of areas of discussion

 

Conducting the interview

·         Appear professional and unbiased

·         Record all information

·         Check on organizational policy regarding tape recording

·         Be sure you understand all issues and terms

·         Separate facts from opinions

·         Give interviewee time to ask questions

·         Be sure to thank the interviewee

·         End on time

 

Post interview follow-ups

·         Prepare interview notes within 48 hours

·         Prepare interview report

·         Have interviewee review and confirm interview report

·         Look for gaps and new questions

 

Questionnaires

·         A set of written questions, often sent to a large number of people

·         May be paper-based or electronic

·         More cost-effective than interviews

·         Select participants using samples of the population (e.g. convenient, random, purposive, stratified)

·         Design the questions for clarity and ease of analysis

·         Administer the questionnaire and take steps to get a good response rate

·         Questionnaire follow-up report

 

Observation: Directly observing users

·         Watch processes being performed

·         Users/managers often don’t accurately recall everything they do

·         Checks validity of information gathered other ways

·         Serves as a good method to supplement interviews

·         Be aware that behaviors change when people are watched, thus it is difficult to obtain unbiased data

·         Be unobtrusive

·         Identify peak and lull periods

 

Document and Procedures analysis

Types of information to be discovered

·         Problem with existing system

·         Opportunity to meet new need

·         Organisational direction

·         Names of key individuals

·         Values of organisation

·         Special information processing circumstances

·         Reasons for current system design

·         Rules for data processing

 

Four types of useful documents

·         Written work procedures

o   Describes how a job is performed

o   Includes data and information used and created in the process of performing the job or task

·         Business form

o   Explicitly indicate data flow in or out of a system

·         Report

o   Enables the analyst to work backwards from the report to the data that generated it

·         Description of current information system

 

Modern Tools

Joint Application Development/Design (JAD)

·         A structured group process focused on determining requirements

·         Involves project team, users, and management working together

·         Purpose: collect systems requirements simultaneously from key people

·         Very useful technique, conducted off-site

 

JAD Participants

1.             Facilitator/Session leader

·         Trained in JAD techniques

·         Sets agenda and guides group processes

2.             Scribe(s)

·         Record content of JAD sessions

3.       Users and managers from business area with broad and detailed knowledge

4.       Sponsor

5.       System analyst

6.       IS staff

 

Conducting JAD sessions

·         Formal agenda and ground rules

·         Top-down structure most successful

·         Facilitator activities

o   Keep session on track

o   Help with technical terms and jargon

o   Record group input

o   Stay neutral, but help resolve issues

·         Post-session follow-up report

 

Post JAD follow-up

·         Post-session report is prepared and circulated among session attendees

·         The report should be completed approximately a week to two after the JAD session

 

Prototype

·         Repetitive process

·         Rudimentary version of system is built

·         Replaces or augments SDLC

·         Goal: to develop concrete specifications for ultimate system

·         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

 

Selecting the Appropriate Requirements-Gathering Techniques

·         Type of information

·         Depth of information

·         Breadth of information

·         Integration of information

·         User involvement

·         Cost

·         Combining techniques

 

Comparison of Tools

Financial Analysis Tools

NPV = å PV(future cash inflows) –

                                                å PV(future cash outflows)

PV = Cash flow amount

             (1 + interest rate)n ,   where

    interest rate = required return

    n = number of years in future

·         If NPV >= 0, Project is OK

·         If NPV < 0, Project is unacceptable

 

Break Even Analysis

·         How long before the project’s returns match the amount invested

·         The longer it takes to break even, the higher the project’s risk.

 

Systems Documentation Tools

Process modelling

Graphically represent the processes that capture, manipulate, store and distribute data between a system and its environment and among system components

Process model (replica, copy)

·         A formal way of representing how a business system operates

·         Illustrates the activities that are performed and how data moves among them

 

Data Flow Diagrams (DFDs)

·         Graphical representation of data as it passes from one step to another

·         DFDs are used to consider data without bothering about the equipment used to store it

·         DFDs are used as a first step in describing a system

Elements of a DFD

1.      Process

·         An activity or function performed for a specific business reason, e.g. calculation

·         Manual or computerized

2.      Data flow

·         A single piece of data or a logical collection of data

·         Always starts or ends at a process

3.      Data Store

·         A collection of data that is stored in some way

·         Data flowing out is retrieved from the data store

·         Data flowing in updates or is added to the data store

4.      External entity

·         A person, organization, or system that is external to the system but interacts with it.

·         Either a source of data, such as an order form from a customer or part of the system which uses/consumes the data, called a sink

 

Creating DFDs

·         DFDs start with the use cases and requirements definition

·         Use case is a set of activities required to give out a particular output

·         Generally, the DFDs integrate the use cases

·         Names of use cases become processes

·         Inputs and outputs become data flows

·         “Small” data inputs and outputs are combined into a single flow

·         Create DFD fragments for each use case

·         Organize DFD fragments into level 0 diagram

·         Decompose level 0 processes into level 1 diagrams as needed; decompose level 1 processes into level 2 diagrams as needed; etc.

·         Draw one process representing the entire system (process 0)

·         Find all inputs and outputs listed at the top of the use cases that come from or go to external entities; draw as data flows

·         Draw in external entities as the source or destination of the data flows

System Flowcharts

·         A diagram which gives an overall view of a system

·         Shows the path taken as data pass from one organisational unit or processing machine to another within a company

·         Shows the tasks that are performed on the data e.g. sorting or updating

·         Shows the type of storage media used to hold data e.g. magnetic disk, magnetic tape etc.

·         Generally, the emphasis of flowchart is on people, activities, documents and media

 

Decision Making Tools

Introduction: one of the major challenges for a Systems Analyst is to effectively communicate the system requirements to a diverse audience.

This entails taking facts harvested from stakeholders and presenting them in a readable form, with enough detail to facilitate testing and other downstream activities.

Analyst can describe complicated business logic by way of decision tables and/or decision trees.

 

Decision Tables

What is a decision table - Table representing complete set of conditional expressions where expressions are mutually exclusive in a predefined area

A decision table lists causes and effects in a matrix. Each column represents a unique combination

·         Purpose is to structure logic

·         Cause = condition

·         Effect = action = expected results

·         Applied in Business Analysis, Programming, Testing, Hardware Design, etc.

 

Steps to create a decision table

1.       List all causes in the decision table

2.       Calculate the number of possible combinations

3.       Fill columns with all possible combinations

4.       Reduce test combinations

5.       Check covered combinations

6.       Add effects to the table

Decision trees - Describe a decision’s rationale or process. Using a decision tree diagram makes it much easier for everyone—analyst, presenter and audience—to see how a decision was made or should be made.

Creating a decision tree

1.       Start by structuring the problem—consider the alternatives and consider the outcomes for each alternative.

2.       Follow some rules: outcomes flow from left-to-right or from top-to-bottom.

3.       There are three types of nodes: leaf or terminal node, chance node and decision nodes.

4.       It helps to use different shapes for each type of node, but it is not required

5.       Start with a box at the top or left of the diagram.

6.       Enter the trigger event or decision statement

 

Example: Let’s look at the product line decision

The text version: “Extend or Consolidate”

·         Extend - Traditional or rapid development

o   Traditional
§  Cost is $150,000
§  Revenue $500,000
§  Profit = $350,000

o   Rapid

§  Cost $80,000
§  Revenue $100,000
§  Profit = $20,000

·         Consolidate - Enhance or maintain

o   Make Enhancements

§  Cost $30,000
§  Revenue $60,000
§  Profit = $30,000

o   Maintain products

§  Cost $0
§  Revenue $10,000
§  Profit = $10,000

 

The other decision making tools include the financial tools, and optimizing tools

Optimizing Tools – Includes tools such as linear programming, simulation and queuing

Programming Tools – Includes the following tools:

·         Structured programming

·         Pseudo code

·         HIPO charts

·         Flowcharts

0 comments for "SYSTEM ANALYSIS - SYSTEM DEVELOPMENT TOOLS"

Back To Top