Flaw #9 Physical Percent  (mike vergis - 03/01 22:28:42)

Flaw #9 Physical Percent
Ever wonder why computer generated programs do not calculate the Project Total Physical Percent Complete? Not being able to have a computer generated Physical Percent Complete is the biggest Flaw of all. Not knowing where a project really stands in relation to its contract completion date is not a good thing. Without having a computer generated result that makes an equitable determination of the Physical Percent Complete, monthly project invoice payments are left to old fashion negotiations between contractor and owner representatives. Not having indisputable computer driven results for monthly schedule updates can cause projects to error in making excessive overpayments or underpayments as well as mistaken results for overestimating or underestimating progress.

Cost loaded schedules is one method that is commonly used as a measurement for progress, but costs are not reliable for many reasons. There are many work activities that are not listed in the schedule, there are activity costs that are purposely inaccurate (front-end loading), there is paid for stored material that is not installed, in some schedules there are activity line items that do not have costs assigned and many costs do not have anything to do with construction items, and other costs that are lumped into other line items. With that in mind cost data taken from a cost-loaded schedule will produce a monetary physical percent complete, but it should not be the only method used. It needs to be verified with other methods that calculate the physical percent.

It should be noted that there are at least a half-of dozen methods for determining physical percent complete. None are perfect since scheduling is an imperfect operation, but each will get a result that is in the ballpark. Certain physical percent calculation methods are better than others, which is dependent on the quality of the schedule, so it is wise to use a comparison method of three or more different calculations in order to settle on a finalized completion monthly percentage. This is certainly much better than someone?s bias opinion.

During a typical walk-thru inspection for the purpose of updating duration percentages and physical percentages, the scheduler and inspector walk into a room with four walls. Two walls are painted and two are not. The original duration for the work is four days. Two of the four walls are painted; therefore, the scheduler enters 50% on that line item. This observation has nothing to do with time, it is a physical observation. The interpretation is 50% physical completion and 50% time used. In the summary line of the original duration column the Duration Percent is computed, but in the Physical column, it is not; even though the observation was physical. No one that I know has ever walked into a room as in this example and wrote in a time observation. Who cares anyway? Whether it took one day to paint two walls or two or three, it does not become part of the physical percent equation. Now, if there were no further adjustments to the schedule, the duration percent summary could also be considered as a good approximation of the physical percent. So what are the chances of this happening? ZERO, well maybe! As soon as the GC scheduler starts making adjustments, deleting activities, adding activities, changing relationships, changing durations, changing calendars, correcting the float, and who knows what; there is no reliable physical percent remaining. The Duration Percent becomes a Time calculation only and usually a bad one at that. The most important result in evaluating the construction progress, Physical Percent Complete, is gone and the program is not bringing it back. If only out-of-sequence activities were adjusted, the Duration % Complete and the Physical % Complete could be construed as the same and offer some approximation on the state of construction progress. As stated above, schedulers should make two submittals, one unadulterated by changes that would give a physical percent (duration percent) result that is reasonable and the other submittal with approved changes to serve other purposes going forward. Again, verify with other methods for computing physical percent.
   
   

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