Microsoft Office Tutorials and References
In Depth Information
How Tasks Become Codependent
In Chapter 4, I mention that you shouldn’t set task start dates very often
because projects are fluid — they change and grow faster than bad guys
come at you in the average computer game. If you build in timing logic rather
than assign specific dates to tasks, Project can reflect changes by adjusting
your project based on that logic.
If the task of getting materials in-house is delayed by a week, for example, the
dependent task of starting the manufacturing process moves out a week
automatically. You can note the change when you’re tracking activity in your plan,
and Project makes adjustments accordingly. The alternative is to go in and
change the start date of just about every task in your schedule every time a
task is running late — you don’t even want to think about doing that!
Dependent tasks: Which comes first?
As with human relationships, every dependency relationship involves roles:
Every task is either a predecessor or a successor. Any two tasks with a timing
relationship can be a predecessor-successor pair, even if the timing of the
two tasks overlaps or they’re set to happen concurrently.
Figure 6-1 shows you how the taskbars in Gantt Chart view graphically depict
the predecessors and successors in dependency relationships between tasks.
Notice how taskbars represent the relationship when a task starts after (or
during the life of) another task. Also notice the lines drawn between tasks:
These lines indicate dependency links.
Here’s some important advice about dependencies, so listen up: You can
have more than one dependency link to a task, but don’t overdo it. Many
people who are new to Project make the mistake of building every logical
timing relationship that could exist. If things change and the dependencies
have to be deleted or changed (for example, to shorten a schedule), the web
of dependencies starts to get convoluted — and can easily create a nightmare.
For example, you must complete the tasks of obtaining a permit and pouring
a foundation for a building before you can start framing it. However, if you set
up a dependency between obtaining the permit and pouring the foundation,
setting a dependency from foundation to framing is sufficient to establish the
correct timing. Because you can’t start pouring the foundation until you have
a permit and you can’t frame until you pour the foundation, framing cannot
start before you have a permit.