formulas for Actual Duration and BCWP

[DJ Huff]

I have yet to be able to figure out the formulas that derive both Actual
Duration and BCWP when using actual data in my plans. I understand from
where the data is to come, but I have not found a consistent set of formulas
I can use to calculate Actual Duration, which is essential to calculating %
Complete...nor can I figure out how MSP (standalone 2007) calculates BCWP. I
have asked the question on this forum in the past as to how MSP calculates
the EV elements but have not gotten an answer I can use to run calculations
myself and have them = Actual Duration or BCWP I see in the plans.
Documentation says Actual Duration / Duration = % Complete (which is what I
have set for EV). I cannot figure out Actual Duration. It appears it may
use the baseline hours per day within a given period in some fashion, but my
calculation results have been inconsistent. I understood BCWP = % Complete *
BAC, but that has also been inconsistent. Some documentation implies BCWP
uses % Work Complete while others imply % Complete. I need to understand
this to be able to make the proper plan adjustments to keep the plans on
track.

 

[Steve House]

Actual Duration is the amount of calendar time between work began and when
it was last performed. Imagine we had a task scheduled to start last Monday
and was planned to run for 5 days. The resourced worked as planned Monday
and Tuesday then got sick and missed work Wed, Thur and Fri. As of the end
of the day Friday, the task had posted 2 days Actual Duration out of 5 days
Scheduled duration and is 40% Complete (2/5). The resource returned today
and worked all day on it - Actual Duration now is 3 days. The time he was
sick becomes non-working time and those days are no longer included in
duration. He has come to us this afternoon and said "this is bigger than we
thought, it'll take me another 5 days to finish it. Actual Duration (to
date) is 3 days, Remaining Duration is 5 days, Total duration is 3+5=8 days
and % Complete = 3/8 or 37.5%. Nowhere in these calculations do baselines
enter the picture.