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Need for Scheduling Standards

by Craig Lance, CCM, F.SAME


In all the years that I have been involved with scheduling, I yet to find a universally accepted standard for preparing and maintaining construction schedules.  Every scheduler that I have ever met has their own set of rules that they follow.  And who is to say their way of scheduling is any more right or wrong than the next guy.


Scheduling software certainly doesn’t set standards. The AACE International article, CPM Scheduling and How the Industry Views Its Use, by Patricia Galloway, PE, took a poll of academia and the construction industry to find out which scheduling software is being used.  By far, Primavera software was the most widely used; Microsoft Project was the next most widely used software. Also mentioned were propriety software, and other programs such as Excel.  All of these softwares have one thing in common: the user has the ability to create a schedule in some form or another, and then make a multiplicity of changes through all of the options offered in the software. The only limits to the changes one can make, is in the ability to navigate the software. In this way, the schedule can be easily manipulated – either unintentionally or intentionally.

Unintentional manipulation is usually the result of a savvy computer technician who knows how to how to work the scheduling software, but has never been on a construction site or has an understanding of the process. It can also be a new student straight out of school that took a scheduling class, but has no practical experience. An article in the October 2013 ENR, Why the Best Schedulers Don’t Rely on Software by Erin Joyce, made the point that schedules are getting worse not better despite more powerful scheduling programs. It went on to say “Because the software lets the end user do too many dumb things. Most of the people who are practicing scheduling have never been formally trained, and they don’t know what a good schedule or a bad schedule is.”

Intentional manipulation is an ethical decision by the scheduling practitioners.  Schedule manipulation can result from the need to always show the project is on schedule, or proving time extensions and delay damages. An Owner can hold retainage, require a recovery schedule or even issue a cure notice just by a contractor submitting a progress schedule showing the project is behind schedule.  Jon M. Wickwire, one of the authors of Construction Scheduling: Preparation, Liability, and Claims, (Wickwire, Driscoll, Hurlbut and Hillman) noted the following problems with scheduling practitioners: lack of qualified schedulers, failure to perform scheduling responsibilities in a professional manner, widespread software abuses due to ignorance, negligence, and deliberate deception; and failure of all parties involved in the scheduling process to exercise the intellectual rigor necessary for successful project schedules.

There are professional organizations that incorporate scheduling into its curriculum, but fall short of establishing a comprehensive industry standard.  Project Management Institute (PMI), AACE International, and other professional societies and organizations have developed scheduling practices or standards in varying degrees.  I know of one owner that required a time impact analysis (TIA) be performed by the contractor to justify time extensions. The contractor would submit a TIA with its time extension request only to have it rejected by the owner. The owner was always vague in its evaluation of the TIA, but always rejected them. In this case, a TIA was required, but no one knew how to achieve it including the owner and the contractor. This could have been resolved by requiring the use of the AACE International’s Standard Practice No. 52R-06, Time Impact Analysis – as Applied in Construction. It is a straight forward, relatively simple method for preparing forward looking TIAs.

Court cases can set precedence for good and bad scheduling practices. Case law is based on previous court cases and sets legal precedence for claims of similar nature, typically proof of schedule delays.  Not following case law runs the risk that your schedule will be rejected in court. Construction Scheduling: Preparation, Liability, and Claims is a great reference book that is widely used and quite often quoted in terms of scheduling standards.  It relies on case law from which it derives its guidance for preparing and maintaining schedules.  As an example, case law has shown that for a schedule to be credible, it must start with a baseline schedule that has realistic durations and logic as to how the contractor intends to perform each phase of the work. Then periodic updates to the schedule are required to reflect actual work on the project. Specifically, schedule logic must be corrected to actual sequences used by the contractor and to also correct out of sequence work. Durations must also be updated. This is where case law falls short.  I have not found where it specifies which duration should be updated or how it should be done. There are a number of durations that mean vastly different things. Original durations are durations originally established by the contractor to perform a given task. I personally feel these durations should never change, or at least, not without good reason so that the original plan can be preserved. The remaining duration can be updated after an activity starts and has the same effect as changing the original duration, but still maintains the integrity of the original duration. I have talked to scheduling “experts” that have no problem with changing original durations.

Ultimately, it is up to the owner to establish the scheduling standards to be used on a project. This is done through the contract. The U.S. Army Corps of Engineers Alaska District uses a project schedule specification that is detailed and clearly establishes what can and cannot be done on the schedule. However, the schedule specification can be different from Corps of Engineering District to District. The Municipality of Anchorage uses a different schedule specification as does a private corporation that builds franchises throughout the country. The AACE International article, CPM Scheduling and How the Industry Views Its Use, reported the results of a survey from the construction industry. A majority surveyed indicated there was an immediate need for Critical Path Method (CPM) Scheduling Standards. It also showed that a majority didn’t know who should develop such standards.  In conclusion of the article, four recommendations were made: 1) Bring consistency and relevancy to universities on how CPM scheduling is taught; 2) Professional organizations need to come together in collation to address what is required relative to standards and to move those standards to ANSI standards; 3) Certification of schedulers; and 4) Best practice guidelines should be developed sooner rather than later. I personally don’t see anything happening soon. Although, I do concur with the survey that there is an immediate need for standardization in the way scheduling is practiced.