Using histograms to generate S-curves
You can use histograms in Asta Powerproject to generate S-curves, which can provide you with an indicator of the progress of a project according to a cumulative value such as the project's costs, hours worked or duration complete. This topic describes how to create an S-curve based on a project's completed costs and how to export it to Microsoft Excel® once you have created it.
An S-curve is a project management tool that displays cumulative costs, task progress, hours worked or some other quantity, plotted against time. The name 'S-curve' is derived from the S-like shape that such curves usually display - being flatter at the beginning and end and steeper in the middle, as illustrated below:
This typical shape is a result of the way in which most projects progress.
To generate an S-curve based on a project's completed costs:
- Generate a new histogram, choosing to report on the cost centre(s) that you use to monitor the project's costs, and choosing to create a new histogram report.
- On the Report tab of the Histogram Report Properties dialog, give the histogram an appropriate name in the Name field and select Elapsed Days in the Clipboard unit field.
- Click the Graphs tab, select Cost To Date in the grid on the left side of the tab and select Complete Only in the Complete option field, so that only completed costs are included in the histogram.
If you have baselined your project, you can include the planned costs in the histogram - in a second S-curve - by adding another graph displaying Cost To Date, but this time selecting the appropriate baseline in the Data field. If you do this, it is advisable to give each graph a suitable legend in the Legend name field, for example 'Actual' and 'Planned'. - Select the Line radio button for each graph and clear the Allow stacking check box; if the histogram includes more than one graph - one relating to the baseline data - select a different appearance for each graph.
- Click Close to close the Histogram Report Properties dialog and display the S-curve histogram:
To export the S-curve histogram to Excel:
- Right-click the histogram and select Export to Excel. The Histogram Export dialog appears.
- Enter the name and location of the .XLS file to which you want to export the information in the Export file name field and select an Excel template with which to create the .XLS file in the Select an export template field. A dedicated template - S-Curve.xlt - is provided with Asta Powerproject for this purpose.
- Click OK to export the information. You can now open the S-curve in Excel.
Generating an S-curve based on completed duration
If you want to generate an S-curve based on the performance of a resource or on a project's costs, this is a simple task, as illustrated above. However, if you want to generate an S-curve based on a project's completed duration, you must first set up a 'dummy' cost centre and copy duration information into it, purely for the purposes of generating the S-curve. Once you have copied duration information into this 'dummy' cost centre, you can generate an S-curve histogram based on the information it contains.
To set up a 'dummy' cost centre and copy duration information into it:
- Create a new cost centre with an appropriate name, for example Activity Days.
- Ensure that the Duration column is displayed in the spreadsheet. Use the Format Cells dialog to ensure that the column displays duration in the Decimal (4d, 4.4w) format and that the Export time unit check box is cleared.
- Create a new column in the spreadsheet and configure it to display the Cost field.
- Use the Table Definition Properties dialog to specify that the Override time unit field is set to Day for the Duration column and that the 'dummy' cost centre you created is selected in the Cost centre field for the Cost column.
- If any bars in the project have more than one task, display them in one-task-per-line mode so that each task is displayed on its own bar.
- Right-click the Duration column and select Copy, then right-click the column displaying the 'dummy' cost centre you have created and select Paste to paste the tasks' durations into the column.
Now that you have copied the tasks' durations into the 'dummy' cost centre, you can generate an S-curve histogram displaying the values within the cost centre - which will of course relate to the tasks' durations rather than to their costs.