S-Curves Again

[Rami]

Hi

There is something that I dont understand when generating S-Curves

Now, when we need to get S-Curve, for sure we need the time-phased values.
Like, what is the BCWP n certain date. But does project server keep these
values, or it keeps overriding the old values with current date values.

Can you please clear ot for me?

Thanks

 

[John M.]

Rami -

What calculation method are you using for earned value (% complete, or
physical % complete)?

Assuming you are using the default % complete method, then the historical
timephased earned value calculations are calculated based on the % duration
complete up until that period. It recalculates these values as you make
changes to a task. An example might help: you begin with a 4 week task.
After 1 week, your remaining duration remains 3 weeks...so you are 25%
complete and have earned 25% of the baseline. If after week 2, you increase
the remaining work/duration such that the task now spans an additional 5th
week, then the earned value at the end of week 1 is dropped to 20% of the
baseline and the cumulative earned value at the end of week 2 is 40%. It
does not retain a snapshot of the data at the end of each status update.
This behavior makes perfect sense to me, but I have encountered some folks
that truly want a snapshot after each period.

Does that answer your question?

John M.

 

[Rami]

Dear John

Suppose we have 2 -year-project in oil and gas industry.

I want to draw the S-Curve after completing one year in the project.

Now the question is, if you want to draw BCWP curve, how PS will know the
real percent complete that correspond to each month? If it does not keep the
real data, then the curves are not accurate, right?

Regards

 

[John M.]

It does keep the real data. I probably confused things with my earlier
response. Imagine a case where you have a 3 week task. At the end of the
first week, you think you are 33% complete. But as you continue working on
the task during week 2, you realize that more work is actually required. By
extending the timeline and effort of the task, you really were less than 33%
complete at the end of that first week. My distinction was to clarify that
MS Project will recalculate your historic accomplishments based on
subsequent changes...which makes it more accurate. Otherwise, you could
have the situation where you were 33% complete at the end of week 1 and then
only 25% complete at the end of week 2. This just doesn't make sense.

Of course, all of this is relatively moot if you decompose your tasks to
more finite levels where they are either complete or not complete (e.g. 1-3
day duration maximum on average).

John