Work Breakdown Structure(WBS) - Fundamentals

I had joined newly in IT industry and one day my manager asked me , "which WBS item are you currently working on?" I was a month old in software delivery and I didn't know what WBS is...I just smiled and explained him what I am working on.The next day we met again and he explained me all about WBS.

Thanks Sanjeev for explaining.

What is WBS?

WBS is the decomposition of project into smaller components so that the scope of the project can be organised , defined and shared across stake holders.

Following is the sample WBS for a general project management

Note : The details for execution is not shown very clearly.For every phase of execution , control steps are undertaken.Project initiation and Project Closure are one time activities.

         

Why is WBS necessary?

A WBS is necessary as it helps to :

• Estimate cost
• Estimate Schedule
• Plan Resource
• Plan Risk
• Plans scopes properly
• Gives detailed picture of activities            

With a proper WBS in hand , that gets updated periodically it becomes easy to track projects . With proper WBS , a schedule and budget overrun can be minimized.

Is WBS same as Schedule?

WBS is not a schedule , WBS helps to schedule the project properly. With WBS you land up creating a proper schedule.

How do you create a WBS?

Step 1: Identify deliverable.

Step 2 : Decompose the deliverable to come up with work packages.

Step 3: Decompose work packages further to come up with activities.

Step 4: Assign Identification codes to each WBS item.

Step 5:Verify WBS by asking the questions

• Are all the activities identified?
• Are all the activities unique?
• Are all the activities clear?
• Are all the activities complete?
• Is this activity really needed?      

Once you have answered these questions , your WBS is ready to be shared.

What are the inputs for WBS?

Following are the inputs to create a WBS:

1. Project Scope Statement

2. Project Requirement Documentation

3.Organizational processes assets 

Can you get sequence of events in WBS?

It is not necessary that WBS is a well sequenced one , WBS is just to identify what are the various activities that needs to be done during the project.

Once , your WBS is base lined , the schedule is prepared and resource identified , you can start sequencing the WBS activities in the project plan.

But as such WBS items may be not be sequenced,as this is too early a stage to sequence.

What is a work package?

A work package is the smallest unit of purview of a project manager.

For example a project manager might be interested in knowing whether the "Create User" functionality is complete whereas the team lead may be interested in knowing if the code review and unit testing is done or not.

What is an activity in WBS?

A work package can be further divided into activities for example the work package "Create User" functionality can be further divided into:

a. Coding for Create User

b. Create User unit testing

c. Create user code review

What is 8:80 Rule?

Each and every activity identified in WBS are independent , can be developed and tested independently.

So, each of these activities are identified either as a simple activity , a medium activity or a complex activity.

Based on the simplicity/complexity of the activities timelines are defined the minimum time for an activity to complete is 8 man-hrs and the maximum is 80.

What is a Resource Breakdown Structure?

Each activity in a WBS is allocated to one/more resources , using a WBS and an RBS a project plan can be created , so that it can be ensured that resource utilization is optimal.