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S-Curve analysis

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djedilat toumi
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Hello everybody, 

Please, can you comment on this S-curve and give us some explanation about it?

waiting your comments....

regards

5737
construction S-curve .png

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Rafael Davila
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Joined: 1 Mar 2004
Posts: 4476
SCurve123
  • By looking at the Actual Curve end point we know the Data Date. 
  • The remaining late curve for current schedule is missing, shall be something like the one I draw in solid black. 
  • At Data Date the remaining [to complete] early curve and remaining [to complete] late curves must start at same point. 
  • Any revission to current schedule shall include remaining early and late starting at the same point, the last actual point.
  • Usually early curve is above late curve but the use of FNLT constraints can make them intercept at some point and then late curve to be above.  It does not always happens but the S-curves even when not obvious can become meaningless when such constraints are used.  Not all schedulers are aware of this anomaly.
  • There is a reference to interpreting S-curves, the AACE International Recommended Practice No. 55R-09.  I do not recommend it as it misses to talk about the anomaly when using FNLT constraints and even misses to talk about early and late S curves.  Anyway I feel you should be warned about it. 
djedilat toumi
User offline. Last seen 2 days 12 hours ago. Offline
Joined: 14 May 2018
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thank you a lot Mr. Zoltan Palffy.

is it normal to find a curve of the revised plan like this ????

Zoltan Palffy
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Posts: 1849

this is either a manhour or cost based resource driven s curve

the Y axis respresnts the % complete and the X axis respresents a time inter vale (too samll to read) in eather weeks or months

The blue line represents the earliestdates that actviities can be started and completed

The green line represents the latest dates that actviities can be started and completed

The red line represents progress or actuals against the plan

Te red dashed line represents the revised plan 

The dashed lines is the forecasted percentages to meet the revised plan