Introduction to Information Systems Models and Methodologies - High Level Models and Methodologies for Information Systems - page 6

The spiral SDLC model (Boehm 1988 ) proposed a much more complex
approach to the incremental model, where development of the system is built in
successive waves, much like the growing arms of a spiral, while also introducing
the concept of risk analysis in the process.
The rapid application development model, or RAD, was an adaptation of the
incremental model for projects that had very restricted time limits, as it was based
on the concept of establishing time boxes for the development of each build, in an
attempt to bring together IS development and the business goals of the organization
(Gottesdiener 1995 ).
SDLCs can be seen as context-speci

c applications of the principles of the
various system development methodologies. The dichotomy between traditional
and agile has a parallel in waterfall versus incremental, albeit not an exact one.
While methodologies allow for the organization to position the desired information
system within the larger context of the project

' s needs and goals, development life

cycles describe the system s development process in detail, from conception to

deployment. Pinpointing the appropriate SDLC for a given project can provide
developers with a valuable tool for organization and management.

'

1.4 IS Development Methodologies

An IS development methodology (ISDM) can be de system of proce-

dures, techniques, tools, and documentation aids, usually based on some philo-
sophical view, which help the system developers in their efforts to implement a new
information system

ned as a “

(Avison and Fitzgerald 1995, cited by Avison and Taylor
1997 ). Iivari et al. ( 2001 )de

”

c instructions or proce-
dures, constituting a model or general guideline for the goals, tools, and steps
necessary to build a system.
Toward the end of the twentieth century, most ISDM that were in practical use
by organizations and companies were either structural or object methodologies
(Tumbas and Matkovic 2006 ). Essentially, structural methodologies were charac-
terized by rigid, step-by-step descriptions of the

ne IDSM as a set of speci

flow of activities that constitute the
development process, from the analysis of the system ' s requirements to the design

and eventual implementation and maintenance of the final product. Each step is

rigidly determined, and there are no overlaps. Object methodologies focused on the
dynamic aspect of the process of development and perceived each stage in the
process as part of an evolutionary chain of events, leading to the notion of iterative
or incremental development, where the system is released in a preliminary version,
and subsequent versions improve and complete it.
Both structural and object methodologies are now commonly referred to as
traditional methodologies. In essence, traditional development advocates single-
pass development through successive stages, based on extensive documentation and
a rigid perception of requirements. Methods outlined under the traditional scope
aim at being as simple as possible, because the goal is often to make them adaptable