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CPM schedule updating

CPM Schedule Updating Best Practices

In CPM schedule updating practice, there is little consensus on the best way to coordinate and issue monthly progress updates. Larger projects may contractually require an onsite or field office scheduler – someone near the action who has the advantage of first-hand observation – to ‘actualize’ or update progress as it happens, as opposed to after the fact – at the end of the month, which is always an exercise in forensics. 

Schedulers brought up ‘through the ranks’ live either in the field, or close to it, as opposed to being chained to a desk. They have the ability to visualize future sequences in a project and resequence their schedule accordingly. This ability to form a mental picture comes from years of on-hands field experience. However, schedulers are not clairvoyant; if they are not on-site, they are reliant on data-gathering from their team-mates for input.

A schedule can be updated by a field scheduler, or be reconciled by other personnel or subs’ progress payment apps. At a certain level of detail and scale, a scheduler can not solely keep track of all progress. He relies on reports from field personnel, and or payment applications/requisitions. The better part of this data-gathering is validation that guarantees the integrity of the schedule is maintained and that the forward-pass is not out of sequence, or worse, incorrect. 

In the absence of validated data, two potential liabilities arise: the builder has imperfect information for his project control plan, and if he requires validated data for a disruption claim, he simply won’t have it. Owing to industry wide slack project controls, it is the exception that a contractor will successfully win a disruption claim. The reason is that if the claim schedule shows inaccurate information –  such as estimated actual-start and actual-finish dates, and inaccurate % complete – it can easily be refuted by the reviewer, or another observer.   

Because field management isn’t trained in CPM, they need to be oriented in what is to be expected of them in terms of reporting progress. Some like to meet at the end of the month and report verbally, whereas others prefer to complete a spreadsheet. Several platforms allow for collaborative online updating from multiple operators and team members, but I have never seen a project where that happened.

Updating activity progress in Primavera will calculate progress and projections based on the type of percentage complete assigned to the activities. In P6, one can use duration percent complete, however duration percent complete calculates remaining duration as a factor of remaining duration percent. If physical percent complete on a twenty-day activity is entered as fifty-percent, remaining duration is auto-calculated as ten-days, and if remaining duration is calculated as ten-days, physical percent complete is auto calculated as fifty-percent.

Whereas, physical percent complete, below, remaining duration is calculated either by accurate resource tracking, or according to best guess expected finish date.

If a project is not tracking resources and production, it can be hard to know completion percentages. This is especially so for mob/demo, or non-linear activities not executed in one consistent timeline. It’s easier to say, for example, that all Division 9 trades will be done upon the date of substantial completion, but that would not address reported progress in payment applications. Expected finish reporting will not prove helpful for substantiating disruption or delay claims

In rare instances, units percent complete based on actual labor units is employed. These completion types will be contingent on which type duration is used. 

Of the three types of completion percentages, physical percent complete is the most preferred because of the need to forecast accurate expected finish dates that duration percent complete can not always calculate. Projects have expected variable production rates and cost curves that are fairly predictable, however, these variables cannot be represented in P6. It therefore does not help to assume or represent that production rates are evenly distributed. 

For example, a contractor may plan to install 100,000 SF of gypsum board – 65% of which is uninterrupted partition, 35% inside and outside corners, pockets and niches. Although most of the square footage is in the continuous wall, the remaining 35% area may take just as long to install. Given the variable production rates calculating progress for this scope of work would be particularly tedious to accurately represent – a schedule would have to separate the different gypsum board installations according to their productivity rates. 

In addition to percentage types, there is a drop down box for duration and unts types, as well. As a rule, this is typically set at fixed durations and units/time.

Another overlooked update consideration is factoring in material and equipment costs. Many schedules simply don’t break out materials and equipment from labor and production. Thus, if a project manager states 80% project completion, accounts receivable (AR) should be making a separate application for equipment and labor. Otherwise, they are all billed at the same rate as production. If AR is using an AIA G702 payment app, he will be expected to populate the equipment and material stored on site to-date columns individually, or independent of production.

When labor and material is bundled into physical percent complete, early and long-lead procurement skew the level of installed works.

Many contractors rely on vendors and subcontractors for their invoices and progress completion data, some of which validate and synchronize in the master schedule. Without a resource loaded schedule and accurate progress reporting, neither the trades nor the contractor can state accurate values.

Ideally, a project is cost-loaded, work-in-place values are in accord with payment applications, and AR uses values in the project schedule to calculate invoices to ownership. But cost loading is so seldom used, or misused when implemented, that AR develops their own progress calculations independent of the progress schedule. This is what is known as ‘double-entry’ accounting, and puts the veracity of either the schedule or billing into question.

At minimum, a contractor should complete his schedule progress update and then meet with AP to determine if the labor portion of the payment app is in alignment with schedule. Due to limitations in Primavera, and the scarcity of resource and cost loaded schedule, it is rare that an owner can expect builder requisitions to reconcile with the project completion plotted in the schedule. This is often the case, despite boilerplate project specifications that require cost and resource loading. Contractors will either ignore this requirement, or refuse to agree to terms.

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