Information System Development Life Cycle Models - High Level Models and Methodologies for Information Systems - page 29

This issue became more relevant as businesses became increasingly competitive
and IT needed to keep up. When deadlines are the main priority and the swiftness of
software development is critical, RAD presents itself as a very plausible solution.
RAD comprises a set of tools and guidelines that facilitate short-time deploy-
ment, within a prede

ned time frame or “ timebox. ” The product is not developed in

successive steps until a final, complete delivery, but rather it evolves in successive

increments, following the priorities that are established by business — not technical

— necessities (Gottesdiener 1995 ). Some of these tools and guidelines include

planning methods, data and process modeling, code generation, testing, and

debugging (Agarwal et al. 2000 ).
It is important to note that both developers and customers are involved in all of
the increments. However, teams are generally small, highly skilled, and highly
disciplined. They are required to

flexibly adapt to eventual changing requirements
and feedback from customers. Nevertheless, it is crucial to strike the proper balance
between s

design are still necessary (Gottesdiener 1995 ), but not as rigid step-by-step guides
to be followed to the letter (Fig. 2.5 ).
RAD methodologies can follow three-stage or four-stage cycles.

flexibility and structural stability. Underlying models to the product '

“

The four-stage
cycle consists of requirements planning, user design, construction, and cutover,
while in the three-stage cycle, requirements planning and user design are consoli-
dated into one iterative activity ” (Agarwal et al. 2000 ).
During planning, it is possible to analyze requirements, alternatives, and
opportunities, as well as possible risks. This will form the basis for a de nition of

the project s goals and scope, and more importantly, it will allow for the estab-

lishment of the timebox, which is a

'

c increment
of the product is going to be developed. Each increment is then developed in a
spiral-like model, through design, prototyping, and testing. This method essentially
pushes the team closer to the project

fixed period during which a speci

s business goals, by providing key deadlines
that can be determined by market forces (Gottesdiener 1995 ).
While the advantages of the RAD are evident, due to its focus on swift delivery
and effective developer

'

client communication, there are still a number of issues
raised by this approach. One of the most obvious

-

flaws is that it removes a great

Fig. 2.5 Rapid application development entails a succession of increments or versions of the
product, each built on a predetermined timebox and following a cycle of 4 (or 3) steps