Managing Information Technology

Chapter 9 • Methodologies for Custom Software Development 363

Feasibility analysis

Requirements definition

5

25

15

15

13

12

15

100%

$ 50,000

250,000

150,000

150,000

130,000

120,000

150,000

$1,000,000

Definition Phase

Development

Activities

Percentage of

Total Cost

Dollar

Cost

System design

Coding and initial testing

System testing

Documentation and procedures

Construction Phase

Installation planning, data

cleanup, and conversion

Implementation Phase

Total

FIGURE 9.2 Cost Breakdown for $1 Million SDLC Project

the project team. As can be seen from this hypothetical ex-
ample, the Requirements Definition step is the costliest. As
will be emphasized in the following sections, this is a hall-
mark of the SDLC approach: Extensive, up-front time is
spent determining the business requirements for the new
custom software application in order to avoid expensive
changes later in the process due to inadequate definition of
the requirements.
Most SDLC methodologies result in a lot of docu-
mentation. In the early steps, before any computer code is
even written, the specific deliverables from each step are
written materials. An SDLC step is not complete until a
formal review of this documentation takes place.
The traditional SDLC approach has often been re-
ferred to as the “waterfall” model (Boehm, 1981): The out-
puts from one step are inputs to the next step. However, in
practice, an organization could have to take more of a “spi-
ral” approach, returning to earlier steps to change a re-
quirement or a design as needed. Later in this chapter (see
the section entitled “Newer Approaches”), we will discuss
an approach that builds on both the waterfall and spiral
concepts: rapid application development (RAD).

Initiating New Systems Projects

Organizations use a number of approaches to decide which
new applications to invest in. In many organizations, the
process begins with the submission of a formal proposal by
a business department. Some large organizations require
that these proposals first be reviewed and prioritized by a
committee at the department or division level. When sub-
stantial investments and resources are involved, the depart-

ment might be required to wait for an annual approval and

prioritization process to occur. Very large, high-budget

projects could also require approval by the corporation’s

top management executive committee and board of direc-

tors. Some organizations require that a business sponsor,

rather than an IS manager, present his or her proposals to

these approval bodies. Smaller, low-budget projects might

be approved on a much more frequent basis with fewer

hurdles.

At a minimum, a proposal that describes the need for

the software application with a preliminary statement of po-

tential benefits, costs, scope, and risks will be prepared by

business management or an IS manager or systems analyst

assigned to a particular business unit (an account manager).

The extent to which IS professionals need to be involved in

this preliminary phase varies greatly across organizations.

Once the proposal has been approved and IS resources

are formally assigned to the project, the formal SDLC

process begins. For some projects, the initial approval might

only be an endorsement to proceed with a feasibility analy-

sis, after which additional approvals will be required. The

documents for the feasibility analysis then become the basis

for a decision on whether or not to invest in the custom ap-

plication (i.e., a business case for investment). In many situ-

ations, because of the phased nature of the SDLC, the com-

mitment to move forward applies only to the next phase or

step, at which time the business case will be readdressed.

This approach of reviewing a program after each phase or

step, with options to continue, continue with changes, or ter-

minate the project, is called incremental commitment.

Descriptions of each of the eight steps outlined in

Figure 10.1 follow.

Definition Phase

FEASIBILITY ANALYSIS For this first step of the SDLC

process, a project manager and one or more systems ana-

lysts are typically assigned to work with business man-

agers to prepare a thorough analysis of the feasibility of the

proposed system. Three different types of feasibility will

be assessed: economic, operational, and technical.

The IS analysts work closely with the sponsoring

manager who proposed the system and/or other business

managers to define in some detail what the new system will

do, what outputs it will produce, what inputs it will accept,

how the input data might be obtained, and what databases

might be required. An important activity is to define the

scope or boundaries of the system—precisely who would it

serve, what it would do, as well as what it would not do—

and what data processing would and would not be included.

The IS analyst is primarily responsible for assessing the sys-

tem’s technical feasibility, based on a knowledge of current