Defining the activities usually entails coming up with all the tasks needed to produce the WBS work
packages. The question is: When is a sufficient level of detail reached? While there are no hard–and–fast
rules for when to stop with this decomposition, there are a few guidelines. Typically, an activity –
·Can be performed by one person or a well–defined group.
·Has a single, clearly identifiable deliverable.
·Has a known method or technique.
·Has well–defined predecessor and successor steps.
·Is measurable so that the level of completion can be determined.
Another guideline for determining the level of detail needed is the duration of the activity. Usually, a
project manager cannot oversee the task while it is being completed, and will not be able to know the
status of the activity during that time. Thus, if a task takes longer than a few days, a project manager will
not know if everything is working out as planned while the person or group assigned to it is working on
it. In case something does not work according to plan, valuable time will be lost before the project
manager will know about the problem. Limiting the duration of an activity to several hours or a few days
therefore helps to limit the negative impact of any potential delays.
Templates, as part of an organization’s process assets which illustrate “generic” activity lists generated
from information about similar projects in the past, can be used in the scheduling process of other
projects. For example, generating a report or a user interface almost always entails essentially the same
activities, so information from prior projects can reliably be used to accomplish this task.
Expert judgment may be used to better define project activities based on the recollection of a project
expert. However, as the PMBOK guide acknowledges, this method may be less reliable than using
documentation from prior projects. In addition to the experience of a project manager, the experience of
“doers”that is, the people executing the activitiesis a valuable input in the activity definition phase.
For instance, a database manager knows the detailed steps to be performed in setting up certain database
queries.
Often, only the activities to be accomplished in the next few steps of the project can be planned at a
sufficient level of detail. In this case, project managers use a technique called rolling wave planning.
Whereas the closest activities are planned at a detailed level, activities further out in the future are
planned only at a general level. During execution of the project, these activities are planned in more
detail. Thus, as discussed earlier there is a “cone of uncertainty” in which activities are planned in a more
detailed way as the project progresses. As near–term activities are planned in a very detailed way and
future activities are planned in a less detailed way.