Page 105 -

72 Part 1 • SyStemS analySiS FundamentalS

This method takes the five main components of a computer system—(1) external inputs, (2)
external outputs, (3) external queries, (4) internal logical files, and (5) external interface files—
and rates them in terms of complexity.
You can use function point analysis to estimate the time it takes to develop a system in differ-
ent computer languages and compare them to one another. For more information about function
point analysis, visit the International Function Point Users Group’s website at www.ifpug.org.
USING TIME ESTIMATION SOFTWARE. Estimating models, such as the Constructive Cost Model
(COCOMO II), Constructive Systems Engineering Cost Model (COSYSMO), or software based
on one or both of these models, such as SystemStar, work as follows. First, a systems analyst
enters an estimate of the size of the system. This can be entered in a number of different ways,
including the lines of source code of the current system. Then it may be helpful to adjust the
degree of difficulty based on how familiar the analyst is with this type of project.
Also considered are other variables, such as the experience or capability of the team, the
type of platform or operating system, the level of usability of the finished software (for exam-
ple, what languages are necessary), and other factors that can drive up costs. Once the data are
entered, you can make calculations and get a rough projection of the completion date. As the
project gets under way, more specific estimates are possible.

Project Scheduling
Planning includes all the activities required to select a systems analysis team, assign members of
the team to appropriate projects, estimate the time required to complete each task, and schedule
the project so that tasks are completed in a timely fashion. Control means using feedback to
monitor the project, including comparing the plan for the project with its actual evolution. In
addition, control means taking appropriate action to expedite or reschedule activities to finish on
time while motivating team members to complete the job properly.
This section contains an example in which a systems analyst, acting as a project manager,
begins with the basic activities of analysis, design, and implementation. Then the analyst uses
decomposition to break apart the main activities into smaller subtasks, as shown in Figure 3.16.
Then the analysis phase is further broken down into data gathering, data flow and decision analy-
sis, and proposal preparation. Design is broken down into data entry design, input and output
design, and data organization. The implementation phase is divided into implementation and
evaluation.
In subsequent steps, a systems analyst needs to consider each of these tasks and break
them down further so that planning and scheduling can take place. Figure 3.17 shows how
the analysis phase is described in more detail. For example, data gathering is broken down
into five activities, from conducting interviews to observing reactions to the prototype. This
particular project requires data flow analysis but not decision analysis, so the systems analyst
has written in “analyze data flow” as the single step in the middle phase. Finally, proposal
preparation is broken down into three steps: perform cost-benefit analysis, prepare proposal,
and present proposal.

Figure 3.16
Phase Activity
Beginning to plan a project by
breaking it into three major Analysis Data gathering
activities. Data flow and decision analysis Break apart
Proposal preparation the major
activities into
Design Data entry design smaller ones.
Input design
Output design
Data organization

Implementation Implementation
Evaluation