We’re frequently asked if Primavera P6 Professional is capable of displaying S-Curves. Sure, it can do that. You just have to know where to look.
This article is a ‘How To’ on S-Curves in Primavera P6 Professional, how to configure them and how to print them.
What is an S-Curve?
For those of you who are new to the topic, an S-Curve is a simple graph that plots costs, hours, units or other values (depending on the subject matter) over time. They are popular in Project Management because they give managers a quick and easy-to-understand view of cumulative budget, actual and remaining values over the project lifecycle. The term S-Curve denotes the tendency of the lines to form a shallow ‘S’ shape; flatter at the start, steeper in the middle and flattening off again towards the end. This shape is very typical of most projects as the effort ramps up in the beginning periods, stabilizes during the main execution phase and then starts to wind down again towards the Project’s completion.
Primavera P6 Professional can display and publish S-Curves as part of its standard functionality. You can generate S-Curves in the Resource Usage Profile bottom layout in the Activities view, and also in the Resource Profile area of the Tracking view.
The S-Curves in the Resource Usage Profile Bottom Layout
When you first open the Resource Usage Profile it displays a histogram of usage for the selected resource. This histogram is based upon period values as dictated by the timescale setting. So if your timescale bottom tier is displaying weeks, then the histogram bars will be a summary of the total labor units for that week; assuming you’re displaying a labor resource.
S-Curves however, are built upon cumulative data. The line rises each week to reflect the accumulation of labor hours over time. In Primavera P6 the Resource Usage Histogram is set to display the current period bars by default. To change this default you need to do the following:
Right-click in the chart area of the Resource Usage Profile area and in the resulting menu, choose the Resource Usage Profile Options… item.
In the resulting Options dialog, you can deselect the By Date options in the Show Bars/Curves group, and select the Cumulative options as shown below. You can also change the colors of the Budget and Actual options using the adjacent Color buttons.
Click the Apply button to see the results of your changes. It should appear similar to the following in the Resource Usage Profile area.
What are these S-Curve lines telling us about the project?
In the above example you can see that the Budget Units and Remaining Early Units lines are slightly different for the selected resource. The Early Remaining Units line is below the Budget Units line. This indicates that the remaining work for this resource is predicted to cost less in hours than originally budgeted.
The underlying activities are Physical % Complete types, and show that, compared to the original plan, the work is going faster than expected. Because Physical % Complete type has been used on the activities, the scheduler has been able to manually adjust the remaining duration to reflect a more realistic amount of time to complete the work; in this case, less time than planned.
However, if you look at the blue Actual Units line, the resource is overspending compared to the original plan. The blue line is well above the orange budget line. This indicates that more hours are being spent on the current activities than planned. This suggests the work is time-critical and is being managed accordingly.
The predicted Remaining Durations have been reduced on the in-progress activities. This has caused the green Remaining Early Units line to drop below the budget, indicating that the upfront overspending is having the desired affect and the work will likely complete early; assuming this trend continues.
Viewing an Aggregated S-Curve
When selecting individual resources, the Resource Usage Profile shows us what is happening for that particular resource on the project. It doesn’t tell us much about the project as a whole. While one resource may be very productive and showing very favorable S-Curves, others may be not. To better understand the status of the project, we need to see an aggregated S-Curve of all resources working on the project.
By holding the Ctrl key down, you can select multiple resources assigned to the project. With each resource you add to the selection, the S-Curve becomes a summary of those selected resources.
Another way to show an aggregated S-Curve is to use the Tracking view. In this view you can show an Aggregated S-Curve based upon a grouping of resources, without having to select each resource. For example, you could group by Resource Type, and then select the Labor grouping band in the Resource list area in the tracking view.
The S-Curve will represent all the labor resources for the current project (the project currently open), assuming you set the list filter to ‘Current Project’s Resources’.
The result would appear similar to the following:
Printing the S-Curves
Once you have the S-Curves displaying as you want in the Tracking view, or indeed in the Activities view; click on the File menu and choose Print Preview.
In the Print Preview dialog, select Options tab. In here you need to uncheck the Activity Table and Gantt Chart Options. Then select the Profile option.
The S-Curves will appear on the page and you can simply print from here.
You can also save these Print Preview settings in the Layout of the Tracking View or the Layout in the Activities view.
So there you have it; some simple instructions to get you started with plotting S-Curves in Primavera P6 Professional. You can continue to experiment with the Resource Profile options dialog to fine-tune the S-Curves.
For example, see if you can create a plot that compares the remaining early and remaining late units in the project. Remember that all the Resource Usage Profile settings can be saved to a layout in either the Tracking view or the Activities view. This will allow you to open and report these S-Curves whenever you need them.