Introduction to Information Systems Models and Methodologies - High Level Models and Methodologies for Information Systems - page 16

The IS impact measurement model, on the other hand, focused on two funda-
mental aspects of success measurement: impact and quality (Gable et al. 2008 ). It
describes IS success as a result of a combination of different factors: quality (system
and information quality), satisfaction, and impact (individual and organizational).
Instead of perceiving these factors as elements within a causal process, all factors
are independent and exert their in uence through various degrees, with one com-

mon output, IS success. Notably, this model does not consider use of the system as
a signi

cant factor, because there are various instances where system use does not
depend on other variables and is mandatory regardless of user perceptions, leading
the authors to exclude it (Gable et al. 2008 ).
The success of a given information system within its organization is a dif cult

aspect to describe with precision, because it is subjected to numerous in uences.

Different researchers are focused on different variables with more or less emphasis,
leading to the creation of various models whose adequacy to describe IS success
will depend on the purpose of this assessment. Simpler models such as D&M are
ideal for broader considerations. But more speci

c, quantitative approaches will
require more complex models, such as the 3D model.

1.9 Conclusions

We have analyzed the key aspects and contributions to the body of research on IS
development and success measurement. Paradigms, methodologies, SDLC models,
and success evaluation models are all theoretical constructs that aim at systemically
describing the complex reality of IS, in a way that simpli

es not just future
research, but also the work of developers and managers in determining the prin-
ciples and methods of their projects.
There are three degrees for the theoretical approach to IS, illustrated in Fig. 1.7 .
Paradigms offer the broadest perspective, ultimately consisting on the insertion of
different approaches to IS development within the context of a particular philoso-
phy or global view on goals and requirements.
At the development level, IS development methodologies, systems development
life cycles, and Web development methodologies propose varied systematic
approaches to the development process, describing sets of stages, activities, and
roles necessary to achieve successful and ef cient development.

Finally, usability models, quality evaluation models, and success assessment
models allow managers and developers to determine the degree to which the system
is adequate to the goals, needs, and intentions of the users.
As we have seen, the characteristics of the project determine what model or
methodology should be adopted in order to facilitate the development process. In
that sense, a comprehensive study of the different approaches and methods of IS
development can be a valuable tool for developers. We have determined that there
are two principles of IS development: traditional, structured, rigid methods and
agile, incremental, flexible methods. The first category is suitable for large projects,