Rolling Up Physical Percent Complete

A couple of weeks ago, I kicked off a bit of an exercise in personal improvement by revisiting my own understanding of how Microsoft Project calculates Actual Cost and Earned Value measurements.  This post represents a continuation of that effort, as I explore how Physical % Complete rolls up from child to summary tasks.  I’ll admit up front, until I began writing this post, I didn’t realize that Physical % Complete actually rolls up natively within Microsoft Project.

Physical % Complete

First off, let’s take a step back and talk about just what exactly Physical % Complete is.

Physical % Complete is a measure of how “done” a task actually is.  Generally speaking, it’s the most appropriate measure of how done the task is – especially when compared to other typical measures like % Complete or % Work Complete – which track how much duration and work we’ve consumed respectively.

Physical % Complete is intended as a physical measure.  For instance, when building a 10 mile pipeline, after building 5 miles, I would call the task “50% complete” in Physical & Complete.  In software, I would identify rules of credit to define when I am allowed to change Physical % Complete.  For instance, an architectural review may net me 25%, architect approval 50%, customer sign off 100%.  The goal is to make sure everyone understands when and how the credit is applied.

% Complete only tracks how much time I spent to get to that level of doneness.  If I spent 70% of my planned duration building that pipeline, I would be 70% complete within the % Complete field.

Generally, when using these fields, we want to employ the concept of triangulation, i.e. each one of those variables is not important on its own – but powerful in combination.  In the above example, the two points of data for that pipeline project would imply I burned 70% of my duration to complete 50% of my work.

The Mechanics of Rolling Up Physical % Complete

The first thing I might point out is that I was always under the impression that it didn’t and that each child task was independent in how the value was calculated.

In this project, in fact, it doesn’t roll up.

image

A funny thing happens though when we add the Earned Value Calculation Method field into the mix and toggle it to Physical % Complete on baselined tasks.

image

Physical % Complete does roll up….but only when all tasks have been flagged to use the Physical % Complete method – and have also been baselined.

Here’s what happens if we leave one task flagged to use % Complete:

image

None of the relevant subtasks roll up to a common parent task any more. 

The next step is to figure out just what calculations are occurring.  As far as I can tell, we have a simplified form of Earned Value working here.  Going back to the original example:

image

…we can replicate the calculations by multiplying the Physical % Complete X the baselined cost of the task.

  Baseline Cost Physical % Complete Earned Value Calculation
Project Summary Task $13,200 6%   $750/$13,200
Summary1 $2,000 38%   $750/$2000
Task 1 $1,000 50% $500  
Task 2 $1,000 25% $250  

Great.  So now we figured this out.  What do we do with it?  Honestly, I am not entirely sure.  But at least it’s out there, and I can refer to it as I come back to coach my client through the various EVMS calculations.

There’re also a couple other salient points as I see it:

  • Physical % Complete may not be edited in summary tasks.  If we wish to manipulate Physical % Complete on summary tasks, we would need to ensure that all subtasks have cost assigned and are kept updated.
  • In environments where we do not plan on tracking cost at the lowest level, we are effectively required to use % Complete as an Earned Value calculation method.

Both good things to note….

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Rolling Up Physical Percent Complete

6 thoughts on “Rolling Up Physical Percent Complete

  1. Andrew, this is a great post! I work with clients all the time who use MSP and Cobra and this is always a gripe. Not that you can’t calculate EV in Cobra, but the lack of a visual in MSP of progress made always illicits a groan. Thank you and great job.

  2. Yeah, good job. I tell clients not to worry about it… because it is like a solution looking for a problem… Furthermore, SPI and CPI calculate as they should on summary rows, so it does no matter wha the physical % on summary rows computes to.

  3. Thanks for this great post Andrew. I just want to add another thing about this feature … something disappointing actually about 2010 version.
    In earlier versions (both 2003 and 2007) the ability to calculate P%C with different baseline cost values works fine. However in 2010, if you change Baseline for EV Calculation (File>Options>Advanced>EV Options for this project), it doesn’t perform calculations properly with selected Baseline(X) Costs (still it does with Baseline Cost only!).

  4. Arun Nair says:

    Hi
    What do i do if i there’s a summary task such as concreting which has three subtasks.
    1.pouring concrete 1 day duration weightage 50 per cent.
    2. Allowing for cure 7 day duration. Weightage 25 per cent
    3 Removing the formwork 2 days . Weightage 25 per cent

    Physically my major task is concreting and by the end of 1st day i want to show that 50 per cent of task is completed.
    How can i overcome this issue in Msp.

  5. You would need to make the cost for the tasks commensurate with weighting, i.e. task 1 = $5000, 2 = $2500 and 3 = $2500. That would then roll up as needed per the calculations in this post.

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