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Work Breakdown Structure (WBS) & Activity List to Project Success

Sid's been a therapist and life coach for over 30 years. He seeks out the best ways to succeed in life.

WBS and Activity List: What's the Difference?

Many project managers use the terms Work Breakdown Structure (WBS) and Activity List interchangeably. This is okay on small, simple projects. But it can get us into a lot of trouble as we become responsible for larger and more complicated projects, especially ones that involve teams with special skills or use sub-contractors.

Here's the confusing way of saying it:

  • A WBS is a list of what we are making.
  • An Activity List is a list of what we are doing.

Think this way, and they sound pretty much the same . . . and you're headed for trouble.
So let's think about it differently.

  • A WBS is a list of the components of the deliverable.
  • An Activity List is a list of the activities we will engage in during the project.

Now they sound quite different. We need both, and the right order is: Make the Work Breakdown Structure first and make the Activity List second.

How Important is it to Separate the WBS From the Activity List?

I once straightened out a $10 million project that had already wasted $600,000 and was going nowhere for six months. They hadn't made a separate activity list from their WBS, and everyone was doing the wrong job. I worked with the team for just two weeks, and we straightened it all out. Once team members were thinking through their own work and making their own Activity Lists, everything got clear and straight, and the project was back on track.

Think of a Dinner Menu . . .

Imagine you are a caterer, and you are making a list of items that will be served at a prearranged dinner with no special orders. You might have a list like this:

  • Seafood bisque
  • Caesar salad
  • Chicken Marsala
  • Sauteed mixed vegetables
  • Pasta
  • Tiramisu

Lovely! And what you see above is the Work Breakdown Structure (WBS) of this dinner. The activity list would look like this:

  • the shopping plan - what stores to go to, and what to buy at each store
  • the recipes for each item, with cooking instructions
  • the work of plating, serving, and cleaning up afterward

A WBS lists items; an activity list describes processes.

When Do We Make the WBS and the Activity List?

The creation of the Work Breakdown Structure and the Activity List is a turning point in project planning. The WBS is created as the finest level detail of defined project scope, after progressive elaboration. It completes our work on scope planning and prepares us to plan all eight other areas of project management, including time. And the first step in detailed time and cost estimation is the creation of the Activity List. The Activity list must be prepared so that we can create our PERT chart.

A good WBS makes the transition from scope planning to time planning easy. Once we know clearly what we are making, it is easy to plan how we will make it.

Who Makes the WBS and the Activity List?

Between the WBS and the Activity List, there is a big shift in who is working on the project. Creating a WBS calls for a lot of customer input. Customer communication is performed or coordinated by the project manager. And the work of building the WBS is done primarily by the project manager or by designers who know how to elicit customer requirements.

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In contrast, the Activity List is best prepared by the actual workers who will be doing the work. If they describe how they will do their own work, then the Activity List is more accurate. More importantly, guided by the project manager, the team can find very efficient ways to work quickly and prevent problems. Teams who plan their own work and are self-managed create great stuff at low cost. As team members prepare the activity list, they get highly motivated and focused, so the project is on its way to success.

In construction, the WBS is made by the architect or an architectural designer on his team. Then the general contractor will check and modify the WBS, and, working with the actual construction foremen, develop the Activity List.

In computer programming these days, we often have programmer analysts who do both design and application development. In that case, the person doing the work does not change. But the role does change. If you do this type of work—and I do—it is a good idea to picture yourself changing hats. Put on one hat to listen to customers and do design, and a different hat to be alone and plan the activities of your work.

The set of utility shelves I built using the WBS and one of the activity lists in this article

The set of utility shelves I built using the WBS and one of the activity lists in this article

A Case Study: Building a Utility Shelf

This case study should make the difference between a Work Breakdown Structure (WBS) and an activity list completely clear.

I built a set of utility shelves in my laundry room. There are three shelves on one wall, each 3 feet long. Here is the WBS:

Utility Shelves Work Breakdown Structure

3 wood shelves, 3' x 8" x 3/4"
6 braces, 9" long, two to hold each shelf
2 adjustable wall mounts to hold the braces
6 screws to bolt shelves to the wall
6 anchors to hold screws into the wall

The photo to the left shows you what the shelves look like, by the way.

Three Possible Activity Lists for One Project

To show you how different an activity list is from a WBS, I'm going to create three different activity lists, each of which uses the same WBS to create the same set of shelves:

  • The D-I-Y (do it yourself) list can be done by someone with carpentry skills.
  • The home repair hobbyist does it himself, but doesn't do carpentry.
  • The "hire a professional" solution looks quite different!

Activity List #1: The Do-It-Yourself (D-I-Y) Approach

  1. Buy anchors, screws, wall mounts, and braces.
  2. Buy two 8' x 8" x 3/4" pine shelving boards and walnut stain
  3. Cut three 3' shelves from the boards.
  4. Stain the boards, and let them dry.
  5. Measure locations in the wall for the wall mounts.
  6. Mark locations of the screw holes.
  7. Check screw hole locations with a level.
  8. Drill 6 holes, and place 6 anchors in walls.
  9. Mount 2 adjustable wall mounts with 6 screws, screws set loosely.
  10. Tighten all screws.
  11. Attach braces to wall mounts.
  12. Check braces with a level.
  13. Place shelves on braces.
  14. Clean up.

Activity List #2: The Home-Repair Hobbyist Approach

  1. Buy all items on the to-do list, including pre-cut, pre-stained shelves.
  2. Measure locations in the wall for the wall mounts.
  3. Mark locations of the screw holes.
  4. Check screw hole locations with a level.
  5. Drill 6 holes, and place 6 anchors in walls.
  6. Mount 2 adjustable wall mounts with 6 screws, screws set loosely.
  7. Tighten all screws.
  8. Attach braces to wall mounts.
  9. Check braces with a level.
  10. Place shelves on braces.
  11. Clean up.

Activity List #3: The Hire a Professional Solution

  1. Buy all items on the to-do list, including pre-cut, pre-stained shelves.
  2. Hire a handyman to install the shelves and clean up after himself.
  3. Pay the handyman.

Three Different Activity Lists for One WBS

As the old saying goes, there's more than one way to skin a cat. You see above three different ways of doing the same project; three different activity lists. And you can see that each one would have a different schedule and a different budget, as well.

Keep Your WBS and Your Activity List Straight

So, the lesson is: Keep your WBS and your activity list separate, and keep them straight.

On a small project, especially if you're doing all the work, you can run them together.

But on a project with a team, or a project where there might be different approaches worth considering, do the WBS first, and then work out the activity list. And if you can, have the team build their own activity list.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


Kathy on April 19, 2019:

Great article. Clearly explains the differences with simple real-life examples. Thank you!

johnvem on December 04, 2018:

this post is really the most clearer explanation

Pan on July 31, 2018:

your "wbs" is a "pbs"... i cant say your explanation is 100% correct...

fortunate on June 03, 2018:

How can I do a work break down structure and activity list for a sole trader super market

Amjad on March 11, 2017:

iam a student of Project Management ... your example has really made me understand the difference between WBS and activity list in a very simple way . thanks

Ashish on September 30, 2016:

Thank you for providing the clear difference between WBS and Activity list

Tarek M. on August 05, 2016:

Many thanks for the nice article , I am studying for the PMP exam and your explanation made it very clear to me !

TJ on November 20, 2015:

The dinner menu example just made it so clear...i didnt even need to see the one about the shelves..good super article..ill come back for more preparing for my pmp exam.

Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on January 31, 2015:

Hi Sabrina:

The WBS would contain elements, such as "cake" and "venue." The activity list would contain the actions necessary to have that element ready for the wedding. So "cake" in the WBS might be "1. choose baker; 2. choose type of cake; 3. order cake; 4. pay for and pick up cake; 5. bring cake to venue." Or, if you're baking your own cake, the activity list would be "1. choose type of cake; 2. get recipe; 3. buy ingredients; 4. bake cake; 5. bring cake to venue." So one WBS element can be achieve by two different ways of getting there, two different activity lists.

Sabrina on December 07, 2013:

thank you for your explanation! but in case of a wedding, how are we supposed to do the WBS? I just can't do the difference between them...

Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on October 04, 2012:

Hi KrisL - I'm glad to be able to explain important things from technical sources in ways that work for everyone. I taught tech and management to adults for over 10 years - my writing comes from my speaking, and my speaking comes from my talkative family!

KrisL from S. Florida on October 03, 2012:

Like the two first commenters, I really like the examples: They make the differences crystal clear.

I also like your straightforward and unaffected writing style . . . you are good at writing just enough and not too much to explain things.

Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on October 01, 2012:

Thanks, Leah. Cooking is a great way to teach about process and product. My best-seller on project management (Entrepreneuer Magazine's Ultimate Guide to Project Management) uses cooking examples all the way through. I was once lucky enough to sit on an airplane next to a professional chef who had read my book - and he told me that what I wrote was right on. That cheered me up.

Sid Kemp (author) from Boca Raton, Florida (near Miami and Palm Beach) on October 01, 2012:

Thanks, Robert. I'm glad I was able to break down the Work Breakdown Structure for you. Actually, my own background is in IT, both software and hardware. I use hardware examples in writing because people can picture them. It's really hard to picture an object-oriented module, now isn't it!

Robert Erich from California on September 30, 2012:

This is a great article! Although I think you are speaking from more of an engineering perspective, I have had experience with this type of thinking when working with programmers to develop a website. It is essential to know the difference between what is being created and what needs to be done to get that created.

I love your analogy using the utility shelf. Certainly helps to break it down!

Great article! Keep up the good writing.

Leah Lefler from Western New York on September 30, 2012:

I love your use of a dinner menu to explain a work breakdown structure vs. activity plan, Sid. I am not familiar with many of the terms, and this was a clear example that helped me to understand the concepts! Your shelf building example is excellent, too - for large-scale projects, it is essential to understand the difference!

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