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SELECTION OF AN OPTIMUM STRUCTURED METHODOLOGY FOR 
DEVELOPING AN INFORMATION SYSTEM; A GENERAL MODEL. 
C.M. Paresi, M.M. Radwan, O.U. Essien 
International Institute for Aerospace Survey and Earth Sciences ( ITC ) 
P.O. Box 6, 7500 AA Enschede, The Netherlands 
KEY WORDS: Information Systems, Structured Development Methodologies, Optimum Methodology, Evaluation Model. 
ABSTRACT 
Where the overall intent is a realistic and organised control of the System Development process, with a resultant effective 
Information System, then it becomes imperative that the Methodology chosen for the development of the System, should 
be optimum for that Object System. The paper shortly reviews the characteristics of Structured Development 
Methodologies. It then focuses on the determination of a general evaluation model criteria for selecting an optimum 
Structured Development Methodology applicable to a large number of problem domains. An overview of the model is first 
presented, followed by an explanation of the steps in the process of evaluation. 
INTRODUCTION 
In the development of Information Systems which could be 
Administrative, Technical, or Managerial, Structured 
Development Methodologies have been used to create 
systems that give an effective communication between the 
system users, the machines that support the systems 
operations, as well as the human factors in information 
exchange. The bottom line is an efficient and organised 
control of the system development process. 
The number of these Methodologies have of recent 
increased considerably in the Information Science/ 
Technology scene. Some look similar in many respects, 
some use techniques that overlap in concepts, the 
advantages or otherwise of some are more apparent in 
some types of Systems than the others, and some lay 
more emphasis on some aspects of Information Systems 
development. 
Therefore, a research was initiated on the determination of 
a general evaluation model criteria for selecting an 
Optimum Structured Development Methodology applicable 
to a large number of problem domains. 
The philosophy of the model is based on the fact that it is 
unlikely at the moment, to have a single methodology that 
can satisfy all the phases and stages during system 
development. Therefore for a particular Object System, 
development phases/stages are identified according to their 
relative importance. The methodologies are then examined 
for how well they provide for the individual phases/stages. 
Based on the peculiar circumstances of the Object System 
under study, several contingencies/criteria can be 
determined and embedded in a general framework through 
which the methodologies would be evaluated. 
The model makes provisions for levels of detail to be 
examined in the Object System, the levels of decomposition 
to which phases/stages of the Object System can be 
reasonably subjected, and also a means of reducing 
subjectivity inherent in this type of evaluation. It is possible 
to carry out the evaluation either for each phase, or the 
entire phases put together. It can also be decided using a 
contingency sub-model, whether the development strategy 
should be the use of only prototypes, specifying, or a 
mixture of both. The model recognises the influences from 
issues collateral to the Object System. 
WHY STRUCTURED DEVELOPMENT 
METHODOLOGIES? 
Systems Development is a non-trivial task; it costs time and 
money because of the complex nature of modern 
Information Systems and therefore needs a clear step by 
step approach in the process of development. This is the 
concept behind Methodologies. It defines the pieces or 
components, phases and activities that one finds in a 
typical System Development project; and also the interface 
between those components [Burch,1979]. The most 
important factor for the need for Methodologies is the 
limitation of the human mind to perceive and retain all 
information it requires and to act on it promptly [Dippel, 
1969]. 
A Methodology should have as general objectives, to : 
Analyse the complexity of problems and simplify them; 
achieve unity of System Architecture; establish and improve 
interaction between users and System Development Team; 
enable efficient parallel development of Sub Systems; 
achieve sound data analysis and administration through a 
well defined procedural framework [Elving & Kirchoff, 1991]. 
A Methodology should specify: 
How a project is to be broken down into phases, activities 
for each phase, outputs for each phase, when activities 
should be executed, constraints to be applied, support tools 
to be utilized, and how projects have to be managed. 
Techniques (which can be diagrams, tables etc.) should be 
recommended at various stages for carrying out particular 
activities recommended by a Methodology. 
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