In my day-to-day work as a scheduler, I interface with all sorts of construction professionals. I have found that the degree to which they understand the technical and theoretical subtleties of CPM CPM Coordination of baseline scheduling varies widely. One might expect project managers with larger contractors to have more experience than smaller ones, but I find that not always to be so. In the end, they really don’t need many technical skills to be key to the schedule management plan; just good insight and vision of the project.

Insofar as coordinating baseline construction project schedules with contractors and their project managers, I prefer CPM baseline backup from each major or critical-path subcontractor or vendor, including cost and resource loading. That would be in a perfect world. Most don’t have the wherewithal to create a schedule in a scheduling platform, however, I have found that this information can be conveyed in any number of ways – so long as the timeline is accurate, and then incorporated into the master schedule. Good project managers make for the best schedulers.

Some contractors believe that the scheduler works in a vacuum: that he reviews the drawings, develops his estimates according to his own interpretations of available resources and production rates, and develops his schedule based on this limited input. This is a low-level misunderstanding that is quickly dispelled by the notion that it is the opposite; that the contractor tells the scheduler how he sees the project timeline enfolding, and the scheduler then develops the CPM baseline schedule.

It is therefore critical that the project manager understands that he is central to the data gathering process that facilitates the building of the schedule. Thus, let the project manager know on day 1 of his required level of contribution and participation, and the project manager in turn must alert his subcontractors and vendors of their requirements.

When schedulers require, or at least insist on it, contractors are reliant on their subcontractors and vendors to confirm duration, fabrication windows, and delivery dates. Schedulers require certain data, but not all schedulers know they require it, and don’t know to ask. For example, if a custom generator was to be installed for a project, many schedulers might guess at fabrication time, rather than get a hard-date from the supplier. If the generator should wind up in the critical path …

When it comes to subcontractors, scheduling without their input can be a slippery slope. For instance, a scheduler could not guess at duration without knowing a given contractor’s resources and production rates. Yet, he must often do so, if for instance some of the major contracts are not let before the schedule is due. Invariably, he will experience some margin of error that the subcontractor will correct him on, that will necessitate his amending of the schedule effectively, double-entry. This circumstance should always be expected when not all subcontracts are let.

Finally, the scheduler must let the project team know that

• The creation and maintaining of the schedule is a collaborative effort, and that each player is responsible for his participation and contribution.
• When subcontractors and vendors don’t provide timely, sufficient, or accurate back-up, the scheduler must make certain assumptions based on his best guesses
• When schedulers make assumptions, they often use ‘place-holder’ dates to represent their best guess. These dates must be certified before the baseline is maintained.
• Place-holder dates effectively necessitate costly time-consuming resequencing, or double-entry, thus, the fewer the scheduler uses the better for all concerned.