At ALICE, we often get asked the question: “How is ALICE different from CPM Scheduling?” or “How is ALICE different from Primavera P6?”. In this post, we address some of the main ways in which ALICE is unique.
Some historical context
Despite the fact that it was introduced in the 1950s and has barely evolved in the last few decades, Critical Path Method (CPM) Scheduling is still one of the most widely used scheduling techniques in construction today. This scheduling technique is used to plan and control a project and to calculate the minimum completion time for the project, along with the possible start and finish times for project activities.
While this technique seemed adequate in the absence of more sophisticated alternatives, the fact is that it has failed to adapt to the increasing scale and complexity of modern projects (especially mega projects).
As a result, planning and scheduling shortcomings are a contributing factor to budget overruns and schedule delays on a vast majority of large projects.
So let’s break down some of the key differences between the way ALICE works and the traditional CPM scheduling method.
ALICE: more than scheduling software
First and foremost, it is important to note that ALICE is much more than scheduling software. ALICE is a comprehensive construction simulation and optimization platform, of which one of the outputs is fully resource-loaded schedules. In that sense, it is unfair to even compare ALICE with traditional CPM scheduling software such as Primavera P6 or Microsoft Project. But since people asked, we are here to answer.
Perhaps the most fundamental difference is in how the methods are used.
In traditional CPM scheduling, your objective is to create a schedule. You take a look at some drawings to understand what you’re building, and start transferring your understanding of the project into individual tasks. You then add precedence logic and durations for each task, repeat hundreds of times, and at last, you have a single schedule.
Automatic schedule creation
ALICE is quite different. You start by defining an objective (e.g.: “I want to create an early master plan for my project” or “I want to figure out my crane strategy”).
You then bring all the necessary information in one place, such as your 3D model (if you have one, but it’s not necessary), your labor, equipment, material quantities and costs, production rates, etc. and finally you assign sequence logic to create what we call “recipes.” From that point on, ALICE automatically generates fully resource-loaded schedules for you, alongside a 5D representation of your project (3D + cost + time).
Recipes contain all the information required for ALICE to understand how to complete elements of your construction project (labor, material, equipment, durations, production rates, etc.)
Ease of rescheduling
Because ALICE is parametric, exploring new scenarios and rescheduling take minutes instead of days or weeks. All the user does is to define new parameter values (e.g.: adjust the number of available crews, or change productivity rates based on how a project is actually progressing) and click a button whenever they want to reschedule.
“It could take you weeks or months in P6, what ALICE can do in seconds"
Senior Projects Control Scheduling Manager at Parsons Corporation