How does “Top Down Estimation” in Primavera P6 work?

In Primavera we have a function called “Top Down Estimation” which help us to calculate an estimated figure for Labor and Non-labor unit based on “estimation weights”. It can apply to WBS and Activity.

I will show you how to do it.

We have a simple project and each activity is assigned the resource “Test”. By default each activity will have 40 units.

We will use Top Down Estimation to redistribute the unit to make it more realistic.

To perform top-down estimation, you must first assign estimation weights to WBS and activities. These estimation weights are used to determine how units are distributed among WBS and activities.

Go to WBS window. Show “Est Weight” column.

Now we enter the weight for each WBS.

Go to Activities window. Show “Est Weight” column.

Now we enter the weight for each activity.

Go to Tool -> Top Down Estimation

Primavera show you the current units in your project. Now you will enter the new units you want to apply to your project.

Click on Apply button.

Now you can see WBS and activities have new budgeted units.

The units are distribute according to Est Weight which we assigned to them.

For example: Foundation get 40% of 1000 units = 400 units. Bored Pile get 70% of 400 units = 280 units.

With this function, we can quickly distribute units to activities.