Critical-Path Method (CPM) or Short-Interval Planning (SIP)?
May 30, 2022
When it comes time to implement a methodology to manage capital project planning and scheduling, the default response is usually a critical-path method (CPM) scheduling tool, and for good reason — it works as intended. But CPM does fall short in meeting all the needs of a project team for several reasons. It tends to be inflexible, not detailed enough and at times is unfriendly to certain personas on a capital project.
This is precisely why the need arises to use a combination of CPM and short-interval planning (SIP) with the goal of increasing communication and efficiency, leading to a stronger understanding of project deliveries. To fully grasp why, a brief refresher on what each method entails and what they provide project teams is a helpful place to start.
The Critical-Path Method
Since its adoption in the early 1960s CPM has shown time and again how brilliant it is at establishing activity durations, dependencies and the overall project delivery goals. Projects of all sorts can benefit from CPM — manufacturing, aerospace and defense, and product development to name just a few. Most construction projects use it as a contract document, something submitted monthly to provide stakeholders a holistic view of project health and progress updates on the path of construction. But when handed to field operations, it often struggles to provide enough insight for planning and executing work at the daily level.
The Short-Interval Planning Method
SIP was developed as a means to manage the fluid nature of executing work in the field. Breaking down work into more manageable components and allowing for assignments of more detailed resources leading to the identification of any potential constraints before the work begins. Field operations enjoy the flexibility of moving equipment and crews around throughout the week to maximize utilization in operations. The problem lies when users of each, CPM and SIP, update or make changes that don’t sync up with the other — an all too common occurrence.
Risks When CPM and SIP Users are Siloed
It could be argued that there are two main groups of people working off the project schedule at any given time. First, there is the project controls group. Think of project management, planners and schedulers, and project engineers. They are focused on the CPM schedule. Preparing it for communication to the client, stakeholders and partners.
Then you have the field execution team. Think of superintendents and supervisors — those building the work. These roles benefit greatly from the more granular nature of planning in SIP, for example, when there is a need to rearrange work sequence.
Yet whether steps move or split, they are difficult to maintain in the CPM and require a freer and more dynamic environment to thrive. So naturally, if each persona operates in their own view of the world and the systems are not connected, major problems and confusion are likely to arise.
How Technology Answers These Challenges
By combining each method — CPM and SIP — into a single digital environment, teams can have access to information they normally wouldn’t be exposed to in separate or analogue systems. Let’s take the classic example of the misalignment between the two schedules. When a field execution team requires the need to rearrange their work sequence, SIP is the place where they update the plan.
However, with the traditional tunnel vision that comes from using only SIP, they can lose sight of how changes reflect in the context of the overall CPM plan. The risk of breaching the planned CPM activity or not knowing any better can lead to some serious miscommunication. Examples of these problems are just as serious the other way around. If a field execution team is required to make such changes, the project controls team needs to reflect those changes in the CPM to ensure accurate reporting to stakeholders.
Both CPM and SIP have their proper places as preferred methods on capital projects. You’d be hard pressed to find any project team that doesn’t possess the desire to march toward a unified goal of cost, schedule and overall project certainty. So, why should technological systems not mirror what teams need? Today’s planning and scheduling tools deliver just that, a single digital experience that closes any potential gaps in information critical to project success. So, is it CPM or SIP? The answer is: BOTH.
Ready to take a deeper dive? InEight can help get your projects where they need to go and help you create a solution or view that matches your needs while leveraging your teams’ existing strengths. Let us show you how.