Which of the following curves/line represents the total project cost versus time in the best way?

Explanation:

S-shaped Curve 

• It best represents the total project cost vs. time because of how resources and spending typically progress in a project.

• Initially, spending is low during planning and mobilization.

• Then, costs accelerate rapidly during peak construction or execution phase.

• Towards completion, the cost growth slows down again as finishing and wrap-up activities are less resource-intensive.

• This results in an S-shaped (sigmoid) curve when plotted on a graph.

 Additional Information

Straight Line

• Implies constant spending rate over time, which is unrealistic in most real-world projects.

• It doesn’t account for different phases of activity intensity.

U-shaped Curve 

• Indicates low spending in the middle phase and high at beginning and end, which does not match typical project cost flow.

• Not suitable for depicting total cumulative cost over time.

Parabola

• May represent acceleration of costs, but lacks the initial slow rise and final tapering seen in real projects.

• It's more applicable to instantaneous cost rate (e.g., cost per unit time) than cumulative cost.