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S-Curve equation?

10 replies [Last post]
Mohd Mahd
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how to create an equation for a progress S curve? for sure it will be 2nd degree one. possibly, no equation can do it, as it is some (mathematically) unrelated points. in P3 they offer curve types, but some times not enough! my regards Mohd

Replies

Charleston-Joseph...
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Hi,

If you done some studies in Algebra or Engineering Mathematics, then, you must have encountered that for each series of points plotted in the x-y axis, an equation or formula (value of y for given value of x) can be generated.

The plan S-curve can readily produce an equation, however, for actual s-curve, the equation can only be good up to the actual values. The forcast or trends are usually unstable to the point that no reliable equation can be generated as the project progress till completion.

Cheers,

Charlie
Trevor Rabey
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There is an HTML mistake in the ANZPUG website. Use this link:

http://www.anzpug.org/documents/GrowthCurve.ppt

________________________________________________

This use of the term "S Curve" is very different from its usual understanding in construction and other types of projects, isn’t it? Dr FJ Bromilow of the CSIRO in Australia examined several hundred construction projects of different types and derived the shape of the "typical" construction S curve with time as a function of cost and the way to generate it. Perhaps I can find it.
Rahul Mulik
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Colin,
I tried to access the Power point presentation for S Curve u posted, but the attachement was not in readable format.
Can u please help me out for this.

Cheers & Regards,
Rahul.
David Ahlgren
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Is there a simple way to use an S Curve in a Spreadsheet to show the effect of an adoption rate on the total members in a community
Mohd Mahd
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thanks for ur reply. unfortunately, this what i received, ................. (This is an automatically generated Delivery Status Notification. Delivery to the following recipients failed. jdyer@qal.com.au ................. it looks there's a problem in the email. u have any explanation?
Forum Guest
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We used an equation on my last job If you email Jeff Dyer at QAL Gladstone jdyer@qal.com.au you will get a copy of the equation Alan D
Mohd Mahd
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DEEPLY thanks. u r always great. in appreciation to this info, i really do not know what to say or what to do.
Colin Cropley
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Mohd Here is a website references that gives a formula for S-Curves: http://www.geocities.com/WallStreet/3960/normalsx.html (Integral formula) I will post a Powerpoint presentation (GrowthCurve.ppt(~280k) at www.anzpug.org/resources/Useful.htm which you can download if you wish.
Mohd Mahd
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pls look at it as a what if (for the curve only). yet, i am looking for the possiblity. what could be the area under curve. some questions... analysing a S curve will help, analysing its project progress, along with its basis of, weight factor, importance, manhour,....etc.
Colin Cropley
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Mohd Please explain why you need an equation for an S-curve. The S-curve is normally the cumulative sum of the periodic (=daily, weekly or monthly) planned manhours or costs in a schedule.