Description
Collapsed as Built, also known as “but for”, is a simulation-based technique employed within CPM software such as MS Project or Primavera P6. This approach allows the identification of the earliest possible completion date, assuming that delays from any of the involved parties had not existed.
It is a static logic methodology, the relationships in the model remain constant throughout the various stages of analysis. While methods with dynamic logic are commonly preferred in expert reports, as opposed to those built upon the static logic of the baseline. However, this technique is based in the as-built logic, making it suitable for forensic analyses.
However, applying this method correctly, involves creating a model tightly correlated with as-built dates and all corresponding delay events. It might not be suitable for very extensive projects with numerous activities or without a very clear and defined construction sequence.
To carry out the analysis of delays using this methodology, the following steps must be followed:
- Identify As-Built Program. Locate the As Built program and identify the delays, activity durations, and start and end dates.
- Model Creation. Create the model in some CPM software (MS Project, Primavera P6) with the actual durations of the activities and the delay events that have taken place, identifying their responsible parties. A 7-day-a-week calendar can be used since all the calculations will be directly in calendar days This accounts for activities occurring outside the originally planned work periods. It is possible that certain cases might yield anomalous outcomes. For instance, an activity starting on a Friday and ending the subsequent Monday might exhibit a duration of 4 days, despite only 2 days being worked. This system naturally balances once collapsed.
- Delay Adjustment. Once the model with the delay events, is established the duration of the delays responsible for one of the parties is changed to 0. This allows to calculate the earliest completion date under the assumption that delays from any party had not occurred.
- Repeat for Other Parties: Repeat the same process for delays attributed to the other involved parties.
This method, while potent, demands meticulous construction of the model to ensure its accuracy and applicability, particularly when dealing with intricate timelines and multiple parties.
Strengths of Collapsed as built
- It is a robust method that, if carried out correctly, allows for good expert analysis.
- It takes into account all the delays that have occurred in the project, thus allowing the evaluation of the impact of subcritical routes.
- No need for an electronic baseline or contemporary updates.
- It is conceptually easy to understand and present.
- It allows analyzing concurrent delays and identifying the impacts of delays on each of the parties once the model has been created.
- Few delay analysis technicians apply this method.
- It is a technique that can be applied while the project is running to calculate time extensions or penalty forecasts.
Weaknesses of Collapsed as built
- It does not consider the contemporary programs of the project.
- Creating the model requires a lot of work, great detail in the as-Built information and very experienced technicians in software management and delay analysis.
- Creating the logic to replicate the as-Built conditions requires subjective decisions that may not match contemporary schedules.
- Susceptible to intentional or unintentional manipulation in the modeling process.
- Ignores prospective critical paths in contemporary programs and the critical decisions that may have been made based on them.