The Project Management Institute (PMI®) defines progressive elaboration as “Progressive elaboration involves continuously improving and detailing a plan as more detailed and specific information and more accurate estimates become available. Progressive elaboration allows a project management team to define work and manage it to a greater level of detail as the project evolves.” This concept and definition of progressive elaboration applies to the development and execution of industrial projects. It is mentioned in the previous post that industrial projects follow the five phases shown in the picture. Scope definition starts with a product requirement at the beginning FEP-1 phase. Then the scope definition progresses with more and more details over succeeding phases. While the scope gets more defined over the lifecycle of the project, the execution plan also gets more defined. This is also called the rolling-wave planning philosophy. 

It is also mentioned in the previous post that a project controls manager (PCM) needs to participate in the project management team during all phases of the project start from the beginning of FEP-1. The PCM with help from an estimator and a scheduler, will be the main team member leading the rolling-wave planning philosophy. The rolling-wave planning could run as described below.

Beginning of FEP-1:

• The estimate will be a class 5 estimate as defined by the AACE Recommended Practice 104R-19. This is a rough order of magnitude estimate that is usually based on benchmarking previous projects of the same production capacity. The benchmarking at this phase does not include any details about the quantities that contribute to the scope or how they will be installed. This estimate usually has an accuracy range of minus 50% to plus 100%. 
• The schedule will be as follows:
  • The total duration of the project will be calculated in a similar manner to the estimate based on benchmarking the project to completed projects that produce similar capacity. The execution duration will also be calculated the same way.
  • The schedule of the FEP-1 Phase which is usually a few procedural steps to complete FEP-1 will be a detailed Level 3 schedule. This schedule usually fits in one or two pages.
  • The schedule for FEP-2 will be a top-down Level 2 schedule to show some details of the work to be performed during the FEP-2 Phase.
  • The schedule for FEP-3, Execution, and Startup Phases will be a Level 1 schedule to show the main milestones, key scope breakdown areas, and the project constraints such as the permits, availability of resources, equipment tie-ins, very long lead items, etc. This schedule is not a detailed critical path schedule. It should be treated as a planning tool to indicate the initial criticality of major construction areas, the impact of potential risks that might happen during the project execution, and how to react to project constraints.

End of FEP-1:

• The estimate will be a class 4 estimate as defined by the AACE Recommended Practice 104R-19. This is an equipment factored or parametric estimate that is usually based on previous projects with different production capacities. This estimate usually has an accuracy range of minus 30% to plus 50%. 
• The schedule will be as follows:
  • The total duration of the project will be calculated in a similar manner to the estimate based on parametric model analysis that gets input from completed projects. The execution duration will also be calculated the same way.
  • The schedule of the FEP-2 Phase which is usually a few procedural steps to complete technology selection and economic feasibility analysis will be a detailed Level 3 schedule. This schedule usually fits in two or three pages.
  • The schedule for FEP-3 will be a top-down Level 2 schedule to show some details of the work to be performed during the FEP-2 Phase.
  • The schedule for Execution and Startup Phases will be a Level 1 schedule to show the main milestones, key scope breakdown areas, and the project constraints as mentioned above.

End of FEP-2:

• The estimate will be a class 3 estimate as defined by the AACE Recommended Practice 104R-19. This is a semi-detailed unit costs with assembly level line items estimate that is usually based on published unit costs and productivity levels. This estimate usually has an accuracy range of minus 10% to plus 30%. This estimate typically used for preliminary authorization and for awarding the contracts for long lead items. 
• The schedule will be as follows:
  • The total duration of the project (FEP-3, Execution, and Startup) will be calculated based on the execution strategy and sequencing main high-level activities and milestones. 
  • The schedule of the FEP-3 Phase which is usually usually focused on process and performance engineering will be a detailed Level 3 schedule. This is the first critical path method schedule that can produce the critical path and floats for different activities.
  • The schedule for Engineering Design and Procurement will be a top-down Level 2 schedule to show some details of the work to be performed during once FEP-3 Phase is complete.
  • The schedule for Construction and Startup Phases will be a Level 1 schedule to show the main milestones, key scope breakdown areas, and the construction and operations constraints as mentioned above.

End of FEP-3:

• The estimate will be a class 2 estimate as defined by the AACE Recommended Practice 104R-19. This is a detailed unit costs with forced detailed take-off estimate that is usually based on published unit costs and productivity levels. This estimate usually has an accuracy range of minus 5% to plus 20%. This estimate is typically used for final funding authorization. 
• The schedule will be as follows:
  • The total remaining duration of the project (Construction and Startup) will be calculated based on the execution strategy and sequencing main activities and milestones. 
  • The schedule of engineering design and procurement will be a detailed Level 3 schedule. This is critical path method schedule that can produce the critical path and floats for different activities. This schedule will be used for tracking and reporting the progress of engineering and procurement.
  • The schedule for construction and startup will be a top-down Level 2 schedule to show some details of the work to be performed during once during these two steps.

Mid-Engineering and Constructibility Review:

• No change to the estimate at this time. The cost engineers would be tracking any changes from the original estimate and providing monthly forecast. At this time a change log would be part of the project documents and 
• The schedule will be as follows:
  • The schedule for engineering design and procurement will be tracked and updated to re-forecast the beginning of construction. 
  • The schedule of construction and startup will be a detailed Level 3 schedule. This is critical path method schedule that can produce the critical path and floats for different activities. This schedule will be used for tracking and reporting the progress of construction and startup. The input to this schedule would be the detailed schedules from different construction contractors.