The four methods are recognized by AACE in Recommended Practice 29R-03 “Forensic Schedule Analysis” (“RP 29”)1 and by the Society of Construction Law (SCL) in their “Delay and Disruption Protocol”2 (the “SCL Protocol”).
• As-Planned vs. As-Built (“APAB”)
• Contemporaneous Period Analysis (“CPA”)
• Retrospective Time Impact Analysis (“RTIA”)
• Collapsed As-Built (“CAB”)
These are the traditional methods mostly used in dispute situations. The choice of method is largely determined by the quality of the schedules. The CAB is particularly sensitive to poor quality logic in the schedule, as a stepped removal of tasks can draw attention to errors in the logic associated with the critical path.
The implication of the AI data is that it is becoming easier to find all the facts and the drivers associated with a particular delay (often even where the event that is in fact the driver is not on the contemporary schedule). The increasing ability to review data means that the “as built” should be a document that can be agreed between the Parties. In the view off the author in the era of AI the Parties should be in a position to agree the “as built” or to continue to work on that together in a non-contentious way until the “as built” critical path is identified and agreed. From this point the comparison with the “as planned” is really a comment on the quality of the contemporary records. If the “as planned” can be reconciled to the “as built” with the addition of some additional impact events then the quality of the contemporary records is good. If the “as planned” can be reconciled with events that have been correctly claimed under the contract, then there is a strong likelihood that the Contractor will win the case. If however the explanation of the “as built” is hard to reconcile to the “as planned” then the lack of a good correlation means that another method needs to be chosen, or the Contractor does not have a good case as a matter of fact.
In the view of the author the “blind sight” of the Contractor at the date of the schedule update is not relevant to determining what happened. The “hind sight” will show what actually happened. The intentions of the Contractor in terms of “blind sight’ relate to the extent to which the error of the Contractor (in making wrong predictions) was culpable or made assumptions that lead to wrong or over optimistic actions which did/did not impact on the progress of the works. In the past the idea of knowing the hundreds of thousands of facts about the project was unthinkable. However now live input feeds into BIM models for the designers, and the possibility of taping every conversation and even every chance conversation at the coffee machine with recording buttons on the glasses, it means that almost everything can be known, and given to the AI computer for review. With this in mind it is only a matter of computing power and cost to extract the driver of every significant decision made on the site. This in combination with AI makes the range of possible disagreements on narrative much smaller,as both Parties are subject to factual attack on any narrative which does not stick closely to the “as built” reality.
In this context the methods above are going rapidly out of date, as they relate to analysis of schedules which generally are not resource driven, and in practice most schedule durations are driven by the limited resource availability of the Contractor rather than limitations of method. There are obviously exceptions to this, but by and large resource output rates and resource availability are the key drivers of duration, and the main point is that these methods are related to reviewing old schedule types that do not fit with the modern possibilities of planning and planning review.