If you want to assign resources to your project schedule, but don’t wish to utilize the Role features of Primavera P6, you can take the simpler approach of naming labor resources by their skill. This will allow you to avoid tying yourself down to specific named individuals. Primavera P6 allows for the assignment of labor, material, and equipment costs to your schedule. Primavera P6 also displays the allocation, and, possible over-allocation of labor resources throughout the project. Labor resources may either be generic or specific people.
This article discusses the assigning of generic resources to activities to find the total labor cost of the project. It does not discuss the assignment of material or equipment resources. Also, this example uses the standard 5-day work week calendar.
Primavera P6 Scenario
Our sample project is a straight forward pipe and thrust block installation, Figure 1. The activities are all sequential and have the standard Finish-to-Start relationship.
The only exception to the norm is a 3-day cure time delay lag on task C – Pour Concrete. Assigning a cure time lag is discussed in another article entitled “Primavera P6: Scheduling a 24-hour Elapsed Time Lag”.
Defining Resources In Primavera P6
The first step in the resource allocation process is to first define your resources. For our example all our resources will be shown as generic skills instead of specific employees or team members.
To get to the define resource screen select Enterprise | Resources from the main drop down menu at the top of the screen. Once you are at the Resources screen you will be able to view resources in your project system.
If you are not seeing resources in your system, you probably have a filter in play, so select Display | Filter By: All Resources, Figure 2. You should now see all the resources in your database.
For our five day work week calendar example make certain the Default Units/Time in the Resources bottom layout Details tab is set to 8.0h/d.
Click the + Add button on the upper right hand of the screen or select Edit | + Add. Type in the Resource ID and Resource Name. In this example the first resource will be used as a top-level resource for a named group. Enter an ID and a name for your resource group, Figure 3.
Use the Move tool group on the right hand of the screen to move your company over and up in the hierarchy, Figure 4.
Your top-level resource should now appear at the top of the list of resources, Figure 5.
To add individual generic resources to your project database simply select Edit | + Add, and fill out the pertinent information in each column. The Resource ID is typically an abbreviation of the Resource Name, which appears in the next column. The Resource Type will be Labor for all our resources. The Default Units/Time will be 8-hours/day for our standard 8-hour day calendar.
Select the bottom details view from the Bottom Layout tool group at the top of the screen. Enter the Standard Rate of pay ($ per hour) in the bottom details, Figure 6.
Your Total Engineering Incorporated resources for our example would be as displayed in Figure 7.
Make certain the Effective Date for each resource in your schedule is current. The Max Units/Time is the maximum hours/day your generic resource is allocated to work in a day. Note that if you have three resources that are all the same generic type your Max Units/Time will be 32 hours/day, using the standard calendar. We’ll come back to this later, but for now make your Max Units/Time for all your resources 8-hours/day.
Before we begin our resource assignments we want to make certain of two things. 1) Set the Edit | User Preferences: Calculations: Resource Assignments toggle to “Recalculate the Units, Duration, and Units/Time for existing assignments based on the activity Duration Type”, Figure 8.
2) Now that we set the toggle to recalculate based on the activity Duration Type, we need to verify that all our activities have the correct duration type.
The Duration Type defines how Primavera P6 should behave when we assign multiple resources to it or make changes to one of three possible attributes of the assignment; namely the activity duration, units or units/time. In other words, which corner of the duration triangle do you want to lock down, the activity duration, the activity units (total sum cost in hours for the activity) or the resource units/time (e.g. hours per day).
The corners of the duration triangle are shown below in Figure 9.
This idea of the duration triangle is to illustrate that a change in value on one corner will require a recalculation of one or more of the other corners.
For our example set the Duration Type of all activities to ‘Fixed Duration and Units/Time’. Duration is fixed because we have already determined the activity duration, which we do not want to change. We also want the Units/Time value to be fixed. For example, if we add one resource to the activity it gets assigned a default of say 8 hours per day.
If we add a second resource to the activity, we want it to also use it’s default 8 hours per day. With Fixed Duration and Units/Time, adding a second resource increases the only remaining unfix variable: Units, so the total cost in hours for the activities goes up.
We will be adding resources to each task and adjusting the Units/Time. So we will compute the Units (or Work) performed for each task by fixing the duration, adjusting the Units per Time, and calculating the Units.
Note that Units/Time is the daily effort of a resource. The Units/Time format is set in the Edit | User Preferences: Time Units: Units/Time Format, and may be shown as a percentage or hours/day. For our example we will display the Units/Time in hours/day.
Now assign your resources to individual activities. This is done using the Add Resource button at the bottom left hand of the screen, Figure 10.
Make sure you add the Resources and Budgeted Labor Cost columns to your list of columns in the Activities View, Figure 11. Each generic resource is assigned to each respective activity only once.
Note for Activities B – Set Forms and C – Pour Concrete we want four generic common laborers working on each of these tasks. How can we have four laborers working on a task when we’ve only assigned the common laborer once to each respective task? Well, this 4-laborer effort on a tasks B and C is modeled by making the Budgeted Units/Time 32-hours/day, corresponding to 4-laborers each working an 8-hours/day shift, Figure 12. Set Tasks B and C to 32-hours/day and Task D to 16-hours/day, corresponding to 4, 4, and 2 laborers on each task, respectively.
Now select the Resource Usage Profile icon from the bottom layout tool group at the top of the screen, Figure 13. Note to view the Resource Names for the current project Select Display: Current Project’s Resources: Filter By: Current Project’s Resourses. Select Common Laborer from the list of Resource Names and you will see the resource allocation and over-allocation of the common laborer, again, Figure 13.
Yes, our Common Laborer is over-allocated on tasks B, C, and D. If you’re resource constrained, this might be an issue and you may wish to consider using resource leveling to see when activities can occur based upon the resource availability constraint.
If not, you have generated a good requirements profile for how many laborers you’ll need over time for the project. If however you have your own staff, and can’t exceed the pool, you might wish to adjust the limit of your pool to better reflect the staff you have available to perform the work.
You can do this in the Resources view using the bottom details area. You can adjust your Max Units/Time for this resource either for the entire project or for each day. Let’s say we have 4 common laborers available to work the first week of the project. So make the effective date 4-Jan-2015 and change the Max Units/Time to 32-hours/day. This accounts for all 4 common laborers for the first week of work. Let’s say the second week of our schedule we have 2 common laborers. Select + Add and enter an effective date of 11-Jan-2015 and a Max Units/Time of 16-hours/day. See Figure 14 for common laborer schedule Max Units/Time, and effective dates.
Now view the Resource Usage Profile again, Figure 14. Our common laborers are now under allocated on Monday, Tuesday, and Friday, but exactly allocated on Wednesday, Thursday, and Monday. And, congratulations, there are no over-allocations. The last step before we arrive at our project labor cost is to select Tools | Recalculate Assignment Costs, and then click the Recalculate button in the Recalculate Assignment Costs dialog. Note that our total labor cost for the project is $10,896.00: we now have a labor budget for our schedule.
We looked at just a couple of approaches to adjusting Primavera P6 resources and Duration Types and some thoughts about setting the resource pool. Which methods you employ will depend on your particular time or resource constraints. However it does show that Primavera P6 is an exceptionally flexible tool not only for modeling project duration, but also for resource allocation analysis and for estimating the project cost.
Several generic resources can be assigned to one task by adjusting the Budgeted Units/Time. The resource can be allocated appropriately by adjusting the Max Units/Time, for each respective time period of the project. Primavera P6 also displays the cost for each task, each work break down structure deliverable, and the entire project.