Define Activities Process – Decompose Work Packages Into Activities

Define activities process is all about breaking down each work package from work break down structure (WBS) into smaller activities, to estimate each activity.

So the first step in this sequence is to define the scope, create the work breakdown structure (WBS) and prepare the scope baseline.

Eventually work breakdown structure (WBS) is an output of the decomposition of the scope of work into work packages which are manageable to account for.

Once we have the work breakdown structure (WBS), the next logical step is to define activities in the project. This is done by breaking down each of the work package into smaller activities. You apply the decomposition  to the level where it seems reasonable to estimate an activity.

Always remember too much of decomposition is also not do any good for the project. Hence the project manager needs to carefully analyze to which level the define activities process needs to use the process of decomposition.

In other words,  define activities will perform the mapping between scope of work, WBS (work packages) and the activities. This will also ensure that nothing is left out from the scope to the deliverables.

Hold on? Why can’t we estimate at work package level?

Project scope decompose into work packages. However work packages are too high level to estimate. Also to have more visibility of activities in the work packages and to have more accurate estimates at activity level, the define activities process comes to the rescue.

Define Activities Process ITTOs

Define Activities Process from work breakdown structure

To reemphasize define activities process will use the scope baseline to breakdown each of the work packages into the activities.

Below are the ITTO s for define activities process.

Inputs Tools & Techniques Outputs
  • Schedule management plan
  • Scope baseline
  • Enterprise environmental factors
  • Organizational process assets
  • Expert judgment
  • Decomposition
  • Rolling wave Planning
  • Activity List
  • Activity Attributes
  • Milestone List


Schedule management plan

In every knowledge area, plan provides all methods and approach on how the rest of the processes in that knowledge area are going to perform.

Schedule management plan provides all the information on how the rest of the time management process are going to perform.

Scope Baseline

Eventually scope baseline contains three things.

  • Project Scope statement – Primary artifact to refer to the project scope.
  • Work breakdown structure (WBS) – Decomposition of project scope into work packages
  • WBS Dictionary – More detailed information about each element in the WBS.

Using the scope baseline, the work packages decompose into smaller activities.

Enterprise environmental factors

Enterprise environmental factors are common inputs to many project management processes. Please read through the blog post on common PMP ITTOs for more details on enterprise environmental factors.

In this context, primarily the enterprise environmental factors include

  • Organization policies about the work timings
  • Procedures on how to procure and get access to resources
  • Tools to use, to plan schedule management process
  • Work authorization system

Organizational process assets

Organizational process assets are part of common ITTOs blog post. Please read through the blog post on common PMP ITTOs for more details on organizational process assets.

  • Templates to use for the define activities process
  • Reference to historical information on define activities of similar projects
  • Risks assessments of related to schedule management context
  • Other information from historical projects on when to re baseline the schedule management plan
  • Any other lessons learned from historical projects

Tools & Techniques

Expert judgment

Taking experts opinion on how to define activities in the project using scope baseline. Expert judgement is a common ITTO to most of the project management processes. Refer to common ITTO s for detailed explanation about expert judgment.


Eventually the process of breaking down the work packages from work breakdown structure into activities is called as decomposition. So here the activities are decomposed to the level where it looks reasonable to estimate each activity.

Also the scope management knowledge area uses the decomposition technique, when the project scope is broken down into work packages.

Rolling wave Planning

Since projects are progressively elaborated, we may not know about all the work packages of the project in full detail.

Meaning that at one point of time, we may have full details about some of the work packages which are going to start early in the project, but for some work packages we do not have full detail, for which we need to wait for more information.

Rolling wave planning is a technique that decomposes the only work packages, for which you have required information and also they are planned to start early in the project. So the rest of the work packages are left at milestone level.

As and when we get more information on those left out work packages, we can start the process of decomposing to define activities in the project.


Activity List

Indeed activity list contains all the activities that needs to completed in your project which will cover the entire scope of the project. Activities are at granular level items than the work packages.

Activity Attributes

Eventually activity attributes contain all the information that you need to know about each activity. For example this could be

  • Description of the activity
  • Dependencies of the activity
  • Constraints on the activity, if any.
  • Any other information like duration or resources required, etc.

Milestone List

Milestones are nothing but all the important achievements or check points in your project, which you want to track the progress.

Furthermore in some cases customers provide the milestones as part of the agreement or contract. Besides all othere other milestones could be considerable points in the project that you want to keep track of.


To conclude with define activities process is all about decomposing the work packages into smaller activities in order to estimate each activity.

Also we have seen the ITTOs used in the define activities process.

Finally define activities process outputs the list of activities, activity attributes and the milestone list. These outputs will become inputs to the next process of time management knowledge area, which is sequence activities process.

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