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Have you ever
been asked how far along you were on a project? Of course you have. If you do not have a valid
schedule, or if
you are not keeping the schedule up-to-date, you know that your answer
is pretty much a guess. If you have a
good schedule and you are keeping
it up-to-date, you should have a sense for how much work is remaining
and what the projected end-date is. But are you 50% complete? Or 90%
complete? It is not always easy to know.
Earned value metrics were established
to remove the guess work from determining where you are at in
relation
to a baseline.
Using it allows a project manager to know precisely how far along he
is, how much work is remaining, what the expected cost
will be, and all sorts of other interesting information.
Are you using earned value on your project
today? Probably not. You are not using earned value because your
organization has not adopted it. Implementing earned value on your
project requires a tremendous level of discipline and a common set of
processes. It is hard to apply earned value one project at a time, since
no one else would understand what you are doing and why. It required an
organization focus.
History
Earned value has not been around for
hundreds of years. You can actually trace its beginning to the late
1800s and early 1900s, as managers attempted to make the factory floor
and the production line as efficient as possible. The drive for
efficiency requires a foundation in metrics and earned value was a way
to measure things more precisely.
In the 1960s, the US Department of Defense
began to mandate the use of earned value on defense related projects. As
you might expect, if the government is contracting out projects worth
hundreds of millions or billions of dollars, they want project progress
updates to consist of more than "we seem to be on target." Earned value
calculations can provide a better sense for exactly where the project is
against the baseline and provide an early warning if the trends indicate
that the project would be overbudget or over its deadline.
EVM is based on just three core values.
-
Actual cost (AC). The actual cost of work completed as of a point in time.
-
Planned Value (PV). The budgeted cost of work you planned to complete as of the same point in time.
-
Earned Value (EV). The budgeted cost of the work actually completed as of the same point in time.
Earned Value is calculated by adding up
the budgeted cost of every activity that has been completed. (Remember,
this is not the actual cost of the work activities. This is the
budgeted cost.) Look at the following example:
Today's Date is March 31
Completed Activity
|
A
|
B
|
C
|
D
|
Remaining Work
|
Target Date
|
March 10
|
March 15
|
March 31
|
April 5
|
July 31
|
Budgeted Cost
|
20
|
10
|
15
|
5
|
500
|
Actual Cost
|
20
|
5
|
20
|
10
|
?
|
Let's say that as of March 31 you have
actually completed activity A, B, C and D. Let's calculate AC, PV and EV.
-
AC is the actual cost of the work completed. This is 55 (20 + 5 + 20 + 10).
-
PV is the budgeted cost of the work planned to be completed. This is 45 (20 + 10 + 15). Note that Activity D is not counted since it was not planned to be completed as of March 31.
-
EV is the budgeted cost of the work completed. This is 50 (20 + 10 + 15 + 5).
These three numbers seem to be interesting,
but by themselves they do not tell you too
much. So, we need to combine and compare the values to determine our
status against schedule and budget. Sorry, but this next bit of
information must wait until next week's email.
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