9 Construction Scheduling Techniques and Their Advantages and Disadvantages

1. Excel templates

Construction schedules kept in Excel have their limitations, but this remains an extremely popular method. Excel templates are a simple way to stay organized and keep the details of a construction project together. And about all you need to know is how to work in a spreadsheet format.

Advantages: Excel templates are appropriate for very small, simple projects (even ones bigger than Spot’s doghouse). Since Excel is bundled into Microsoft Office, it’s user-friendly, inexpensive, and accessible. This scheduling technique can be most valuable if only one person is working in the Excel document.

Disadvantages: Most construction planners worth their salt don’t do their core planning and scheduling practice in an Excel template. For one thing, every cell in the spreadsheet must be manually updated, a laborious process requiring constant hands-on attention the moment something on a project changes. It’s also not a collaborative scheduling technique. Sharing an Excel template means there will be multiple versions of the original document with various changes sent via email. This technique will often result in project delays and costly decisions based on outdated information.

2. Critical path method

CPM is the tried-and-true workhorse algorithm. No construction scheduling technique is faster or more efficient at building an initial contract schedule—provided that the inputs are accurate and represent how the work should be done.

This technique develops the initial picture of a project and identifies the resources and time required to complete each milestone, as well as how the set goals relevant to the project. By recalculating the math with different algorithms and computer programs, CPM includes an estimate of the fastest possible time to finish a specific activity.

Advantages: CPM highlights which activities drive the end date of a project. These activities are categorized as having zero “float,” meaning the amount of time a task can be delayed without driving out a project’s end date. CPM helps project managers and participants understand not just which activities are driving the end date of a project, but also which ones “could” jump onto the critical path based on how much float they have. It helps project managers more confidently allocate funding and allot resources to complete the project on time.

Disadvantages: Because the algorithm runs the show, it can seem overly complex and complicated. Also, CPM software can be intimidating to those learning to schedule projects.

3. Program evaluation and review technique (PERT)

PERT is a construction scheduling technique used to estimate project duration, identify risks, and identify most likely activity durations when there’s uncertainty about the estimates. It’s valuable on complicated projects and can be a more visual representation than a CPM.

PERT starts by identifying project tasks and their durations and lays out the milestones indicating progress. Calculations provide the best estimate of the time required to complete each task.

Advantages: PERT gives project managers a clear picture of critical tasks that must be completed on time to keep the project on schedule. A PERT schedule allows for flexibility because it considers both best- and worst-case scenarios.

Disadvantages: PERT is a complicated construction scheduling technique that can be time-consuming. Performing a calculation for each task on a large, complex project could take hours, although with the capabilities available in today’s construction project management software, this isn’t nearly the concern it once was.

4. Line of balance (LOB)

The LOB technique tends to focus on crews and other resources for repetitive construction projects. Think floors of a high-rise building or new tract-home construction.

LOB is very specific and has more to do with resource demand, capacity, and production rates related mainly to work crews. This construction scheduling technique is more common in commercial construction—where work crews are moving from floor to floor or building to building and there’s a need to squeeze out downtime—than it is in residential construction.

Advantages: LOB is great for helping to understand resource inefficiencies. If crews are idle, then the project is losing money. Where is the waste in the profit margin? LOB can help squeeze out the overlap and change the slope of productivity, which ultimately makes the job more profitable.

Disadvantages: The LOB method is much too complicated for small projects. Only a handful of people within a construction organization are likely to be LOB advocates and truly understand it.

5. Qualitative scheduling (Q scheduling)

Q Scheduling, a risk-based scheduling method, is a relatively new construction scheduling approach that uses bar charts to help visualize resource quantities and the locations and times they’ll be needed. Q scheduling also is gaining popularity for its advanced data analysis techniques. Project managers can use Q scheduling to prioritize risks by assessing their probability and impact.

Advantages: Q scheduling is useful for repetitive construction tasks. This method allows workers and managers to see which materials they need and when to order them, follow tasks in sequence, and avoid disrupting others’ work.

Disadvantages: Q scheduling is one of the least common construction scheduling techniques, used only when tasks are repeated but variable quantities of resources are used.

6. Resource-oriented scheduling

Resource-oriented scheduling is similar to the Line of Balance method. It loads resources, mainly labor, equipment, and material (LEM), onto activities to identify situations in which multiple parties will need access to those resources at the same time. This scheduling method is particularly useful where resources are in short supply but are critical for a project to be completed on time and on budget.

Advantages: Resource-oriented scheduling is a super helpful technique to understand when things can and can’t happen. Resource-loading a schedule supplies a ton of rich information.

Disadvantages: It requires constant updating and becomes increasing complicated as a project matures, just as the LOB method does. The more resources for the job and the bigger the project, the more touches it needs.

7. Last planner system (LPS) and pull planning

The last planner system is a workflow method focused on planning and coordinating work at the smallest possible increment, anywhere from one to six weeks, to optimize the use of resources and increase accountability. It’s a collaborative approach whereby the last planners—the people closest to the work being done—make commitments to completing work. Pull planning is a scheduling process that’s part of the last planner system. It involves setting up milestones for project delivery and working backward to identify the steps needed to ensure on-time completion.

Like with the critical path method, the LPS and pull planning techniques began as an analog process. They’ve been done the same way for decades. They involve gathering project stakeholders in a room and literally tacking cards on a wall to visually define what needs to be done and when on a jobsite. Different organizations must come to that card-wall system and put up the things they’re going to do and when they will be done.

Advantages: LPS and pull planning are very collaborative. In the analog versions, people from different disciplines come together. But when COVID-19 hit, planners scrambled for a system to collocate people virtually to conduct LPS and pull planning sessions. Through construction project management software, a digital collaborative experience was devised. There are many who now say they can’t imagine going back to the analog scheduling technique.

Disadvantages: LPS and pull planning aren’t great for analyzing or scaling multiproject and enterprise views. Eventually, construction project managers and stakeholders want to see trends and derive insights across a project—or across 20 projects. A lot of the LPS and pull planning reporting is focused on one job at a time.

8. Gantt charts

Gantt charts, which provide a visual representation of a project plan within a calendar, typically are used to display the CPM, LPS, PERT, LOB, and the resource-oriented and Q schedule methods.

You need a timeline and a list of tasks and activities that need to happen to complete the project. Then you place those events on the timeline. That's a Gantt chart.

Advantages: Most Gantt charts are easy to read. They provide an at-a-glance, visual summary of all the construction tasks and timeframes on a project, keeping the different teams informed and organized.

Disadvantages: As Gantt charts get bigger, they can get harder to read and distill information. Looking at big project timelines in Gantt charts can feel intimidating. Gantt charts need constant updates to keep them current, which can be challenging in fast-paced and complex construction sites.

9. Agile scheduling

Agile scheduling is typically associated with software development, but the construction industry is attempting to adopt some of its tenets. It’s a framework for how to think about sequencing work. Scrums (a collaborative framework that helps teams work toward a common goal) is a common Agile methodology.

Advantages: With Agile management, shifting and working around design changes or unexpected conditions that influence a construction schedule, such as adverse weather and supply shortages, can be simpler to manage.

Disadvantages: Agile scheduling isn’t a construction-specific scheduling technique. That’s not to say that it doesn’t or can’t work within construction; it’s just not as popular. Other techniques are very specific to the built world, with its unique scheduling requirements. Because the construction process is sequential and large projects are scheduled for the most efficient use of contractors and crews, Agile scheduling techniques would need to be adjusted to work with construction’s contractual, schedule, and cost goals to reduce the likelihood of change orders, delays, and cost overruns.