S CURVE REPORTING FOR COST ENGINEERS AND CONSTRUCTION PROJECT MANAGERS
S-curves, a picture is worth a thousand
what the mysterious S Curve is, why it is an important project
management tool, and how to generate one.
WHAT IS AN S CURVE ?
"a display of cumulative costs, labour hours or other quantities plotted against time.
The name derives from the S-like shape of the curve, flatter at the beginning & end,
and steeper in the middle, which is typical of most projects. The beginning represents
a slow, deliberate but accelerating start, while the end represents a deceleration as
the work runs out."
TYPES OF S CURVE ?
There are a variety of S Curves that are applicable to project management
Man Hours versus Time S Curve
Cost versus Time S Curve
Baseline S Curve
Actual S Curve
MAN HOURS VERSUS TIME S CURVE
The Man Hours versus Time S Curve is appropriate for projects that are labour
intensive. It shows cumulative man hours expended over time for the duration of
the project. As man hours are a product of man power and working hours, these
may be adjusted individually or together to ensure the project remains on schedule
COST VERSUS TIME S CURVE
The Cost versus Time S Curve is appropriate for projects that contain labour and
non-labour (e.g. material supply / hire) tasks. It shows cumulative costs expended
over time for the duration of the project, and may be used to assist in the
calculation of the project's cashflow.
BASELINE S CURVE
Prior to project commencement, a schedule is prepared outlining the proposed
allocation of resources and the timing of tasks necessary to complete the project
within a set time frame and budget. This original schedule is referred to as the
Baseline Schedule. From this schedule, a Baseline S Curve is generated. This S
Curve reflects the planned progress of the project.