Types of S-curves —Value and Percentage S-curvesS-curves may be graphed as absolute values (i.e. Man Hours or Cost) versus Time, or as percentage values versus Time. Value S-curvesValue S-curves are useful for determining the Project's Man Hours or Cost expended to date, and Man Hours or Cost to complete. Figure 5: Value Baseline, Actual, and Target Man Hours versus Time S‑curvesAnalysis of the above S-curves reveals the Project as of the 4th of February 2016: - Is 10.5 Man Hours behind schedule (48.5 – 38.0)
- Has grown in scope by 5.0 Man Hours (95.0 – 90.0)
- Has increased in Duration by 1 Day
- Started 1 Day late
- Will finish 2 Days late
- Will require 57.0 Man Hours to complete (95.0 – 38.0)
Percentage S-curvesPercentage S-curves are useful for comparing the Project's performance to either the Baseline and/or Production Schedule. Percentage S-curves (Baseline = 100%)By setting the Baseline S-curve to finish at 100%, the Project's percentage growth (or contraction) may be compared to the Baseline Schedule, and the Baseline % Complete as of the Cut Off Date may be determined. Figure 6: Percentage Man Hours versus Time (Baseline = 100%) S‑curvesAnalysis of the above S‑curves reveals the Project as of the 4th of February 2016: - Has grown in scope by 5.56% (105.56 – 100.00)
- Was planned to be 86.67% complete
Percentage S-curves (Target = 100%)By setting the Target S-curve to finish at 100%, the Project's Actual % Complete may be compared to the Target % Complete as of the Cut Off Date.  Figure 7: Percentage Man Hours versus Time (Target = 100%) S‑curvesAnalysis of the above S‑curves reveals the Project as of the 4th of February 2016 is: - 11.05% behind target (51.05 – 40.00)
In Part 2 of this paper, I will describe how an S-curve is generated.
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Types of S‑curves — Cost vs Time
