8/6/2019 5 Contingency Approach

1/9

11/29/20

CONTINGENCY APPROACH

silan tharakan

CONTINGENCY APPROACH APPLIED TO

DETERMINING ORGANIZATIONALINFORMATION REQUIREMENTS

silan tharakan

8/6/2019 5 Contingency Approach

2/9

8/6/2019 5 Contingency Approach

3/9

11/29/20

silan tharakan

A CONTINGENCY APPROACH TO

CHOOSING AN APPLICATIONDEVELOPMENT STRATEGY

Development should encompass a process to

accommodate requirements and its changes

provide assurance that the application as

developed is an accurate and complete

reflection of user requirements

Once a strategy is selected, methods

appropriate to it can be selected

silan tharakan

8/6/2019 5 Contingency Approach

4/9

11/29/20

Contingencies Contributing to

Requirements Development Uncertainty

basis for the selection of a requirementsdetermination strategy was uncertainty as to theability of users and developers to know and elicit

requirements

selection of an appropriate development strategyto assure correct and complete applicationdevelopment

four contingencies affect the degree of

uncertainty with respect to achievement of anapplication

silan tharakan

1. Project size

Degree: Small, Large

has two characteristics: duration and total

cost

Large project size increases the difficulty of

assuring that requirements are met

silan tharakan

8/6/2019 5 Contingency Approach

5/9

11/29/20

2. Degree of structuredness

Degree: Structured, Unstructured

relative structuredness of the decisions to be

supported by an information system

silan tharakan

3. User task comprehension

Degree: Complete, Incomplete

Comprehension that the user or users have of thetask to be performed by the information system

affects requirements determination anddevelopment uncertainty

If users have a low degree of understanding, the

level of uncertainty for accuracy andcompleteness both in initial requirements andrequirements modification is high

silan tharakan

8/6/2019 5 Contingency Approach

6/9

11/29/20

4. Developer-task proficiency

Degree: High, Low

a measure of the specific training and experience

brought to the project by the development staff

This contingency indicates the degree of certainty

with which the developer will be able to

understand requirements accurately and

completely and develop an application to achievethem

silan tharakan

Selection of Development Strategy for

Requirements DevelopmentAssurance

add control by adopting requirements

development assurance method

Steps of development

1. Measure contingencies and determine the

level of development uncertainty

2. Select a development assurance strategysuitable for the observed level of uncertainty

silan tharakan

8/6/2019 5 Contingency Approach

7/9

11/29/20

Basic development assurance

strategies

1. Acceptance assurance strategy

to accept user statements of requirements ascomplete, correct, and firm and to develop asdefined

lead to greater responsiveness to users whohave well defined needs, elimination of

frustrating assurance procedures for such

users, and an increase in developmentefficiency

silan tharakan

2. Linear assurance process

Requirements can be determined through a

straight forward process with little or no

subsequent modification, a suitable assurance

strategy is to proceed from requirements

specification to final development

Assurance procedures to verify conformance

with requirements

silan tharakan

8/6/2019 5 Contingency Approach

8/9

11/29/20

3. Iterative assurance process

Requirements uncertainty duringdevelopment is moderately high

Include iteration

Whenever requirements are found to be

wrong or inadequate during development, thespecifications are revised by a return to the

requirements determination process withusers

silan tharakan

4. Experimental assurance process

requirements development assurance is

obtained through actual user experience with

the system being developed

achieved by prototyping or simulation of the

application Users and developers can readily identify the

shortcomings of a prototype

silan tharakan

8/6/2019 5 Contingency Approach

9/9

11/29/20

silan tharakan