The following figure shows an S-Curve generated using P6 by a colleague upon my request. This is a twisted S-Curve on which early and lat curve crosses twice, the interpretation of such awkward curve should be explained on the AACE document if it pretends to be reasonably complete. Note this behavior of distorting the S-Curves might happens even if the curves do not cross each other, subtle but still misleading, this shall also be mentioned.
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21 years 7 months
Member for21 years8 months
Submitted by Rafael Davila on Tue, 2013-04-23 15:37
EVM would show something as follows, although for simplicity the figure displays less than half the values available for EVM curves. I never use them so I do not understand them well. On fixed price contracts it adds no value to the owner as at the end earned is equal to budget (or revised budget in case of changes).
I do not use EVM, is not required on my jobs, is an invention of the government suitable for some types of contracts we do not bid, is used mostly on new products development. The EVM jargon is too much for my stomach and nobody at the project site understands it. I do not understand it well, just know some metrics are flawed.
Spide Project apply Earned value but forecast basing on the calculated schedule (not on SPI!). Maybe because they are aware of the flaws. But this could be better explained by Vladimir.
It still has value for the GC to use EVM, just that instead of comparing BOQ Costs he will be comparing his confidential costs to his own confidential budget. Here very few track cost performance using the Job Costing module available on their accounting software. Our job costing culture is so poor it do not even make it to first base. Even when job costing is available we do not attempt to transfer the costing data to our scheduling software, impossible, here every owner wants his favorite software to be used, usually software that cannot communicate with our accounting system. Implementing the communication between all software flavors and the owner/client versions is impractical. The end result is almost no contractor uses EVM.
About Earned Value (Early) and Earned Value (Late) I am not sure all software can display both, most probably only Early.
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16 years 7 months
Member for16 years7 months
Submitted by Gary Whitehead on Mon, 2013-04-22 17:51
I pretty much agree with everything you say. Particularly on the issue of including the forecast element of S-Curves.
Too often I see S-curves which just show historic data. Without the forecast element, an S-Curve is just a projectreporting tool. With the forecast element, an S-Curve becomes a projectcontrol tool.
A project control tool can help influence the outcome of the project, and as such is much more valuable than merely documenting an outcome after the event.
Ref your pic showing a full set of S-curves, to my mind there are 6 S-curves which can provide vaulable information (though it can be a bit confusing to show all 6 on the same graph):
Member for
21 years 7 monthsThe following figure shows an
The following figure shows an S-Curve generated using P6 by a colleague upon my request. This is a twisted S-Curve on which early and lat curve crosses twice, the interpretation of such awkward curve should be explained on the AACE document if it pretends to be reasonably complete. Note this behavior of distorting the S-Curves might happens even if the curves do not cross each other, subtle but still misleading, this shall also be mentioned.
Member for
21 years 7 monthsGary,My picture shows:Planned
Gary,
My picture shows:
EVM would show something as follows, although for simplicity the figure displays less than half the values available for EVM curves. I never use them so I do not understand them well. On fixed price contracts it adds no value to the owner as at the end earned is equal to budget (or revised budget in case of changes).
I do not use EVM, is not required on my jobs, is an invention of the government suitable for some types of contracts we do not bid, is used mostly on new products development. The EVM jargon is too much for my stomach and nobody at the project site understands it. I do not understand it well, just know some metrics are flawed.
Spide Project apply Earned value but forecast basing on the calculated schedule (not on SPI!). Maybe because they are aware of the flaws. But this could be better explained by Vladimir.
It still has value for the GC to use EVM, just that instead of comparing BOQ Costs he will be comparing his confidential costs to his own confidential budget. Here very few track cost performance using the Job Costing module available on their accounting software. Our job costing culture is so poor it do not even make it to first base. Even when job costing is available we do not attempt to transfer the costing data to our scheduling software, impossible, here every owner wants his favorite software to be used, usually software that cannot communicate with our accounting system. Implementing the communication between all software flavors and the owner/client versions is impractical. The end result is almost no contractor uses EVM.
About Earned Value (Early) and Earned Value (Late) I am not sure all software can display both, most probably only Early.
Member for
16 years 7 monthsRafael, I pretty much agree
Rafael,
I pretty much agree with everything you say. Particularly on the issue of including the forecast element of S-Curves.
Too often I see S-curves which just show historic data. Without the forecast element, an S-Curve is just a project reporting tool. With the forecast element, an S-Curve becomes a project control tool.
A project control tool can help influence the outcome of the project, and as such is much more valuable than merely documenting an outcome after the event.
Ref your pic showing a full set of S-curves, to my mind there are 6 S-curves which can provide vaulable information (though it can be a bit confusing to show all 6 on the same graph):
Earned Value (Early)
Earned Value (Late)
Planned Value (Early)
Planned Value (Late)
Actual/Projected Cost (Early)
Actual/Projected Cost (Late)
(NB: All of the above can be measured in terms of money or resource hours)
I'm not familiar with Spider terminology -Does your pic show the first 4 of these curves?
Cheers,
G