Driver Trett Digest Issue 26 - Flipbook - Page 7
DIGEST | ISSUE 26
From the project specific studies, the most widely
accepted method of calculating lost productivity
according to the SCL is the Measured Mile Analysis.
Earned Value is also one of the most reliable
methodologies as can be observed in the figure below.
(i) Measured Mile compares productivity for two similar
tasks when one of them is affected by disruption and
the other is not. This is not always an option in cases
where there is not a section on the works with similar
circumstances to the section that is being analysed that
has not been disrupted.
(ii) Earned Value compares productivity of the task
affected by disruption against the planned productivity
for that task.
WHICH REGION USES IT THE MOST?
EVM is commonly used in the United States, the UK and
in countries where the UK historically has had influence
and involvement such as parts of the Middle East and
Asia Pacific.
EVM is typically used in medium range and large
projects and where there is budget for dedicated project
controls resources.
SUMMARY
To be effective, EVM ought to be set up as early as
possible upon commencement of a project, where
the Cost Breakdown Structure (CBS) and the Work
Breakdown Structure (WBS) may not yet be defined,
in order that they can be defined in parallel. A correct
fit between the CBS and the WBS is a crucial factor in
successful EVM implementation.
On a world where the project requirements are rapidly
growing and where the uncertainty can easily turn the
results of a project from benefits into losses, a correct
EVM implementation is a key objective to understand
the cost and time position of a project at any given
moment, and thus, implement the necessary measures
to mitigate risks and ensure its success.
“Action is the foundational key to all success” –
Pablo Picasso
Figure 4. Reliability of methods quantifying Lost Productivity
When performing an Earned Value analysis, the first
thing necessary is to prove that the planned productivity
or contract productivity is realistic. In order to prove
that one ought to substantiate the productivity used
based on construction cost databases, machine
specifications or other recognised studies in the field.
By comparing both productivities (actual or current vs
contractual or planned) one would be able to evaluate
the loss of productivity.
If the project is divided into windows and sections where
disruption is clearly identified, it is possible to get a
measure of that disruption by applying EVM.
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