A Hammock Activity is a schedule or project planning term for grouping smaller subtasks that hang between two dates.
The sub tasks are not really related in a hierarchical sense. This means that there is no fixed sequence of tasks – any of these subtasks can be done at any time, but there is no particular sequence. The objective is to group dissimilar activities that must be performed to achieve an overall goal, but their individual sequence is not important or logical.
For example, let’s say you have an activity called “plan vacation”. It can have multiple sub tasks like “book hotel’, “get brochures”, “book tickets”, “find a guide”, “check local attractions” etc. Any of these tasks can be done first, without the other being started or completed. But there will be an overall target to complete “plan vacation” by the third quarter of the year.
The size of the hammock, or the duration of the hammock is calculated by the start date of the earliest task, and the finish date of the last task.
The name hammock activity comes from the fact that individual activities hang between the overall dates, floating, just like a hammock.
Example of a Hammock Activity:
As scheduled dates in other tasks change in the network diagram, the duration and start and/or finish dates of the hammock task will change as well. If we are to do three tasks A, B, and C, and task B must start on some date from task A (date A) and task B must finish on some date from task C (date C).
In this case, the Task B can be done between the time it takes to do task A and Task C. If Task A is preponed, then there is much larger time to do Task B. If task C is delayed (takes longer to complete), that means that you also get more time to do task B. Thus Task B is hanging between the start of Task A and end of Task C.
Hammock Activity on the PMP Exam:
Many people have reported questions that use the Hammock Activity in the Network Diagram. There are many good Mock PMP test questions, and you should practice them to get a better understanding.
Hammock Activity in Microsoft Project:
In MS Project, you can break down your task list to make it appear more organized and readable by just indenting and outdenting the project’s tasks to create an outline of the summary tasks (sometimes called “hammock tasks”) and subtasks.
When organizing the tasks for a project, you can group the tasks that share characteristics or that will be completed in the same time frame under a summary task. Project managers sometimes call summary tasks “hammock tasks.” You can use the summary tasks to show the major phases and subphases in the project.
Additional Resources for Hammock Activity: You can read more about Hammock Activity here
PMP Exam Tips & Tricks:
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Vinai Prakash, PMP
Founder & Principal Trainer: PMchamp.com PMP Tips & Online Coaching