If a schedule has constraints peppered throughout and the main effort of operations is to get ahead of their distortion, then you will not predict much atr all with hope. However, if the the schedule creation meetings are created with no constraints and the successful completion is based on performance that reflects capacity, then you can constrain that completion and complete that job on schedule.

The contracts, spec and plans pretty much give me my sequences from design to manufacturing, logistics to site and shell crews mobilization. Once mobilized, the WBS should reflect sitework, underground, slabs, walls to roof level. Dried-in my trades follow through the structure, separated by QA acceptance as they rough-in, install and commission the systems.

Sub inclusions in the schedule creation meetings, experience, historical documentation and local conditions define schedule durations.

I have built and run others' schedules that were pretty reliable in that vein.

When you say contractors, I assume you mean primes or construction management outfits. The trades, typically subcontractors, are extremely reliable in their schedule submissions. They bid based on what they do daily, weekly, monthly with the crews they have in the field.

When the PM or the Planner allows CM upper management promises of Perfect Storms on every day of execution to influence the schedule meetings instead of taking the reliable data of production rates back to the owner to argue that the contract execution duration, milestones, budgeting and so forth need to be negotiated based on the facts of the stakeholders, they are looking for penalties and conflict.

There are a variety of contractors, but the main cleavage is between low-bidders and recipients of Requests for Proposals. The latter is aware of timely delivery of a workmanlike product so that the client requests a product and this contractor tells them how long it takes to deliver what they want at a 15% profit assuring that everyone is happy. The former is the early, or persistent, underachiever. The latter are the survivors who matured, or the subs who grew into primes by having a good handle on their capacities and fought for quality over arbitrary deadlines.