The original version of this paper was published here in May 2009:
See S-curve/intro.htm

This 4th Edition was submitted for publication in January 2019.
It is copyright © Midori Media.
Published here September 2019.

PART 2 | Worked Example | Generating Percentage S‑curves
Using Task Duration as a Quantity | PART 4

Using Task Duration as a Quantity

Extreme caution should be exercised when using Task Duration as a quantity to generate S‑curves.

Consider the following Production Schedule.

Task Name

Start

Finish

Man Hours

% Complete

Duration

MH per Day

Task No. 1

01‑Feb‑2016

05‑Feb‑2016

10.0

40%

5

2.0

Task No. 2

02‑Feb‑2016

05‑Feb‑2016

20.0

30%

4

5.0

Task No. 3

03‑Feb‑2016

05‑Feb‑2016

30.0

20%

3

10.0

Task No. 4

04‑Feb‑2016

05‑Feb‑2016

140.0

0%

2

70.0


Totals

 

 

200.0

 

14

 

Table 12: Production Schedule

The % Complete values represent the Task's physical percentage completion, as inspected on 4th February 2016 (The Cut Off Date).

Task Duration S-curves

The S-curves generated using Task Duration as the Quantity are shown in Figure 20.

Figure 20: Percentage Task Duration S-curves (Target = 100%)
Figure 20: Percentage Task Duration S-curves (Target = 100%)

Analysis of the above S-curves reveals the Project as of the 4th of February 2016:

  • Is 27.86% Complete (Actual)
  • Should be 42.86% Complete (Target)
  • Is 15.00% behind target (42.86 - 27.86)

Task Man Hour S-curves

The S-curves generated using Task Man Hours as the Quantity are shown in Figure 21.

Figure 21: Percentage Task Man Hours S-curves (Target = 100%)
Figure 21: Percentage Task Man Hours S-curves (Target = 100%)

Analysis of the above S-curves reveals the Project as of the 4th of February 2016 is:

  • 7.95% Complete (Actual)
  • Should be 13.00% Complete (Target)
  • 5.05% behind target (13.00 - 7.95)

A comparison of the above figures reveal using Task Duration as a quantity paints a very different picture of the Project's progress as compared to using Task Man Hours as a quantity.

The reason for the variance in the Project's progress is that by using Task Duration as a quantity, the assumption is all Tasks require exactly the same amount of Man Hours per Day. This is often not the case in real life.

In Part 4 I will justify why S-curves are so important as a reporting tool

Generating Percentage S-curves  Generating Percentage S‑curves
PART 4  PART 4

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