Information Technology Reference
In-Depth Information
Task 1
Task 2
Task 3
Schedule
Time
Task 1
Task 2
Task 3
Effort
Figure ..2
Schedule vs. effort in waterfall model.
...
Schedule versus Effort
In the waterfall model, each subprocess in software development strictly follows the
preceding subprocess. The subsequent subprocess always starts after the preceding
subprocess ends. That is why we tackle the design phase after the requirements phase
has been completed, the coding phase after the design phase has been completed,
and so on. So, in the waterfall model, the schedule is always equal to the effort for
the project. Accordingly the software test processes also follow the strict regime that
is followed by the development and design processes (see Figure 4.2).
In agile development, however, things are different. Subprocesses do not strictly
follow the rule that the subsequent subprocess should start only after the preceding
subprocess ends. Due to this, it can happen that a subprocess will start even if the
preceding subprocesses are still being executed. Due to this, the effort can be dif-
ferent from the schedule. In such environments the schedule can be equal to or less
than the effort for the project.
If your project has this requirement, then be prepared to calculate your effort
and schedule accordingly (see
Figure 4.3).
... Task Elasticity
There is another aspect to schedule and effort. Some tasks can be completed faster
either by increasing the loading factor of existing allocated resources or by adding
more resources to the task (see
Figures 4.4
and
4.5)
.
On the other hand, some tasks cannot be completed faster by adding more
resources to the task. One example could be a small task that needs some amount of
preparation. You must include the time required for preparation in your schedule.
