Page 74 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes of function points for a system will remain constant. The only variable is the amount of effort
needed to deliver a given set of function points; therefore, Function Point Analysis can be used
to determine whether a tool, an environment, a language is more productive compared with
others within an organization or among organizations. This is a critical point and one of the
greatest values of Function Point Analysis.
Function Point Analysis can provide a mechanism to track and monitor scope creep. Function
Point Counts at the end of requirements, analysis, design, code, testing and implementation
can be compared. The function point count at the end of requirements and/or designs can be
compared to function points actually delivered. If the project has grown, there has been scope
creep. The amount of growth is an indication of how well requirements were gathered by and/
or communicated to the project team. If the amount of growth of projects declines over time it
is a natural assumption that communication with the user has improved.
Characteristic of Quality Function Point Analysis

Function Point examination should be performed by taught and knowledgeable workers. If
Function Point Analysis is conducted by untaught personnel, it is sensible to take for granted
the analysis will do incorrectly. The personnel including function points should utilize the most
current version of the Function Point Counting Practices Manual.

Current application documentation should be utilized to complete a function point count. For
example, screen formats, report layouts, listing of interfaces with other systems and between
systems, logical and/or preliminary physical data models will all assist in Function Points
Analysis.

The task of counting function points should be included as part of the overall project plan. That
is, counting function points should be scheduled and planned. The first function point count
should be developed to provide sizing used for estimating.
The Five Major Components
Since it is ordinary for computer systems to interrelate with other computer systems, a boundary
must be haggard around each system to be deliberate prior to classifying components. This
boundary must be drawn according to the user’s point of view. In short, the boundary indicates
the border between the project or application being calculated and the external applications or user
domain. Once the border has been established, components can be classified, ranked and tallied.
External Inputs (EI): It is an elementary process in which data crosses the boundary from outside
to inside. This data may come from a data input screen or another application. The data may be
used to maintain one or more internal logical files. The data can be either control information
or business information. If the data is control information it does not have to update an internal
logical file. The graphic represents a simple EI that updates 2 ILF’s (FTR’s). (See Figure 4.1)

Figure 4.1: External Inputs

EI
ILF
B
ILF
A

External Outputs (EO): This is an elementary process in which derived data passes across the
boundary from inside to outside. Additionally, an EO (See Figure 4.2) may update an ILF. The

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