Everything You Need for Studying Critical Path Delay & Recovery

Critical Path Delays always seem to span the entire job, having a compounding effect on a project’s budget. As unfortunate as this phenomenon might be, the reality is delays are inevitable, especially considering all that is impacting the industry today. Ongoing wars, the pandemic, supply chain & resource procurement challenges, and everything else in-between have brought the construction industry more delays than ever before. The natural response of which? To try and recover. 

However, studying delay and recovery strategies after a project completes forces forensic delay analysis and rocky relationships to take form. This article takes a deeper dive into the importance of studying critical path delay and recovery frequently throughout the project lifecycle to ensure projects finish within schedule and budget parameters and stakeholders stay out of court. 


CPM Scheduling & Project Control Basics


Critical Path Method (CPM) scheduling creates a blueprint showcasing the relationships between construction and non-construction activities that are required to complete a project. CPM schedules diagram activity relationships and durations by calculating the longest path to project completion (the critical path). It also highlights how much "float," or room for delay, each activity has in the schedule. 

CPM schedules visualize how work will be completed and should act as your ultimate roadmap to your project deliverables. It is important to emphasize that your project’s schedule must remain high quality because a CPM schedule is the foundation of all project controls. Considering the supply chain and other impacts facing the industry, implementing a project control process is the smartest thing an organization can do and a proper project control process functions best by utilizing a CPM schedule.





Unfortunately, most CPM schedules within the commercial construction industry are not being utilized to their fullest potential, despite all the benefits a project control process can bring to an organization.  Based on a study conducted by SmartPM Technologies, 88% of project schedules are of poor quality, 70% did not keep up with planned progress, 82% of projects were delayed, and 64% of schedules were compressed. 

Low-quality CPM schedules mean you won’t have an accurate roadmap for effectively managing resources or activities, which tends to snowball into other issues that impact projected end dates.  Once a high-quality CPM schedule develops, you can begin accurately studying critical path delay and recovery to assist in navigating through the current challenges within the construction industry. 


Critical Path Delay & Delay Analysis Techniques


Historic Critical Path Delay measures the number of calendar days a project's end date has been delayed due to impacts on the critical path. By definition, anything delayed on the critical path delays the end date of a project. By studying critical path delays throughout a project’s lifecycle, you can determine what drove the project’s end date back and develop a plan to recover against any crucial delays by fixing problems along the way.

To begin doing this, your project team must determine the best way to track, monitor, and quantify critical path delays. Doing so saves an abundance of time in the long run and empowers project teams with the information they need to recover. There are several industry-accepted ways of conducting critical path delay analysis. AACE lists several delay methodologies that you can review to decide which works best for you and your organization, which are summarized below:





As-Planned vs. As-Built

Compares the final “as-built” schedule to the original baseline schedule

Runs on the assumption that the baseline schedule was static and unchanging, analyzing a high risk of being inaccurate with potentially subjective findings. 

Collapsed As-Built Methodology

Takes into account all changes in the schedule from the beginning of the impact period through the end of the project, then reverts all changes to the baseline schedule for analysis. 

Runs on the assumption that all changes to the schedule are accurate and reflect reality; Requires a project to be finished before analysis; Heavily contested in courts, used to discredit the party deploying it.

Time Impact Analysis (TIA)

Inserts a series of activities representing delays and impacts into the schedule to quantify the delay, either prospectively or retrospectively. TIA works if delayed activities are tracked to completion before the delay is quantified and approved. 

If conducting this analysis prospectively, the delays haven't happened yet, making the analysis subjective and, therefore, arguable. If performed retrospectively, this method may assume that the “as-built” data reflects what was known at the time, thus misrepresenting delay. 

Window Analysis

Delay is analyzed between two successive updates, using an as-planned vs. as-built approach but accepts changes in the second update as the basis for the analysis in the next period, or “window.” 

If there are elevated levels of accepting changes to the schedule, then it can be rendered unrealistic due to the likelihood of skewed results.  However, this approach is the industry's most accepted methodology.


Using the Critical Path Method analysis properly, you should be tracking activities to completion and analyzing the impact of the delays in each update period using the windows analysis technique. If something is critically delayed, it is recommended to quantify the delay that the impact caused to the critical path as well as determine causation in real time. That way, two years down the road, you won’t be scrambling to find which event caused the project to go off course. 


Collaborate Over Critical Path Delay


Regardless of which delay analysis method you use, it should always be a collaborative process where delays are discussed monthly amongst project stakeholders with accuracy and transparency. These meetings can be straightforward; here is my recommended approach:

  • Update and analyze the schedule for delays and impacts by looking at planned versus actual progress before the monthly meeting without making any changes to the schedule. 
  • Present schedule findings and discuss them with all parties
  • Discuss schedule changes and mitigation or recovery strategies. Once agreed upon, incorporate these changes into the plan moving forward. 

The meeting’s goal should be transparency and honesty regarding any changes made to the proposed schedule, especially the ones designed to mitigate the historical delay. With all of the unforeseen delays impacting the construction industry today, discussing and studying critical path delays through analysis and collaboration may be the only way to save a project from heading to the point of no return.


Studying Critical Path Recovery


Critical path delays happen.

The critical path is dynamic, and re-prioritizing resources is usually needed to get projects on track. This is typically achieved through modifying the go-forward plan as part of the schedule updating process. 

Making changes to overcome historic delays typically results in compressing the go-forward plan through changing logic, durations, and even entire calendars. This reality presents a risk of schedules becoming overly optimistic and potentially unachievable–which can often lead to more delays, overruns, and, ultimately, disputes.

Because of this, stakeholders must study recovery efforts built into the schedule, which encompasses looking at how project schedules are changed to meet contractual deadlines. These changes should be scrutinized as they pose the most significant risk to completing projects on time and must be understood thoroughly. Furthermore, studying recovery at every update shows what recovery methods are working and which ones are causing more problems than they are solving. 


Studying Schedule Changes for Recovery


It is important to note how critical paths have changed after updates so you can effectively manage your resources. Things will change as your project progresses, and the critical path will likely change as well.

Knowing when that happens means you can effectively manage your resources in that area to make sure things are getting done on time. 


When studying schedule changes, you need to bucket them into three categories: 

  • Critical Changes
    • Studying changes/recovery on the critical path is necessary as the recovery mode may change the critical path completely. The critical path is where you must prioritize your resources most, and studying the changes there is crucial for successful decision-making. This is also the path where changes have the greatest impact on a project's end date. 
  • Near-Critical Changes
    • Even though it has room for delay, the near-critical path should be treated like the critical path because it could easily become the critical path over time. In addition, changes to the critical path frequently pull the date so far back that the near-critical path becomes the critical path. 
  • Non-Critical Changes
    • Non-critical changes are changes that do not impact the end date of the project unless, of course, the changes to the critical and near-critical path activities caused so much acceleration in the schedule that non-critical activities become the critical path. Studying these types of changes is typically the last area of focus when studying recovery efforts. 


After deciphering which type of changes occurred within the schedule, begin quantifying these changes using a half-step methodology to understand where the critical path was before the changes. Understanding where the critical path lies is crucial for allocating resources and staying within time and budget parameters. 


Qualifying Schedule Changes with Half-Step Methodology


Half-step methodology distinguishes past performance delays with the responses to those delays to mitigate the risk involved in schedule changes. It is a process that essentially updates the schedule with no changes made to it and then compares it to a schedule inclusive of any future changes.   Here is how you do it: 

  • Step One- Save a copy of the previous schedule update and add "actual" dates and/or percent completed for all activities that progress in the period. Do not change anything, and save this file as the half-step schedule.
  • Step Two- Create a copy of the half-step schedule and impart recovery strategies and any other changes deemed necessary into this version. The new schedule will be inclusive of all changes and serves as a contemporaneous schedule update.
  • Step Three- Compare the end dates between the "half-step schedule" (step 1) and the contemporaneous schedule update (step 2) to calculate recovery. 


What Information Does Half-Step Methodology Provide? 


If the critical path and end date changed between the contemporaneous schedule and the half-step schedule, then the date changes result from the changes in the period in question. This process can also be used to quantify delay by comparing the end date in the previous update and the half-step update. It also enables an understanding of the result of recovery by comparing the change in the projected end date and the critical path between the half-step schedule and the contemporaneous update. 

Project teams must emphasize studying delay and recovery to understand what the true critical path is. All parties need to know where the critical path is at all times and how changes to it will be quantified. If done correctly, studying critical path delay and recovery across your project portfolio monthly minimizes the risk of delays and disputes. 

Performing a monthly delay analysis and mitigation summary may seem like a daunting task, but delay and recovery analysis is done automatically in SmartPM, giving you more time to focus on project delivery. Get started automating your project control process today with SmartPM. 

Author: Michael Pink

Mike Pink is the CEO of SmartPM. With over 20 years of construction analytics experience, his passion lies in transforming the industry through data.

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