This paper was originally authored by Greg Gendall of Midori Media and published by Project Magazine in May 2003.
It has since been revised and updated by the present author.
It was submitted for publication by Email, February 16, 2009, and is copyright © David Garland.
Published here May 2009.

Introduction | What is an S-curve? | Resource Consumption | Progress Tracking
Using S-curves | Generating S-curves | Actual versus Target | Analysis | Conclusion


Project status

The project will finish late and over budget compared to the Baseline Schedule. Progress to date (i.e. the Cut Off Date) is behind schedule compared to the Production Schedule. Detailed analysis of the project is required to determine why the project will be completed late and over budget. Project growth and/or slippage may be due to a number of factors, including underestimation of effort in the Baseline Schedule, low productivity, rework, variations (approved or not), etc.

In this example, variations may need to be raised to account for the extra man hours expended, and an extension of time claim raised for the later than planned completion. The Production Schedule may need review to ensure tasks have been updated accurately (especially with respect to true percentage complete values), and ongoing and future tasks may require revising.

Generating S-curves

Some software scheduling packages automatically generate S-curves. On the other hand, some (including MS Project) do not. In this case, a third party software application is required to process the Baseline and Production Schedule data to generate the required S-curves.

Midori Media's myPM SCG S-curve Generator is an MS Windows application that integrates with MS Excel to generate the various types of S-curves discussed above. MS Project users will need to export their schedule data to an MS Excel file (easily accomplished using MS Project's File Save As option). myPM SCG processes the resulting export file, and creates an MS Excel Output file containing the required S-curves. These may be copy-pasted to MS Word for inclusion in Project Progress Reports.

The value of S-curves

The S-curve is an important but often overlooked and misunderstood project management tool. A variety of S-curves exist, the most common being Man Hours versus Time, and Costs versus Time. By creating a Baseline Schedule, a Baseline S-curve can be generated. Baseline S-curves provide a basis on which to compare a project's actual status to its planned status. They may also assist in the planning of manpower and financial resources required to complete the project.

A Production Schedule allows Actual and Target S-curves to be generated. These allow the progress of a project to be monitored, and quickly reveal any divergence from the Baseline Schedule. S-curves may also be used to determine project growth, slippage, and progress to date.

Analysis  Analysis

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