Continuing our COVID19 scheduling series: in our previous article, COVID19 | Re-Baselining with Uncertainty, we outlined how to re–baseline the project schedule while planning for continued uncertainty. The likely result of a re-baselined project schedule after a COVID19-related work stoppage is an overall delay to project completion or a significant depletion of project float. In this article, we will review the probable next step: Recovering the Project Schedule.
The COVID19 pandemic has delayed and disrupted construction projects around the globe. As governmental restrictions are easing and projects are re-starting, potential schedule impacts are becoming apparent. In our series, we have reviewed the importance of updating the schedule through the start of impacts and how to re-baseline the schedule to complete the remaining work in the post-pandemic environment. To avoid or mitigate a long-lasting domino effect of impacts from COVID19 disruptions, it may be in the owner and/or contractor’s interest to analyze the costs, time, risks, and challenges to recover the schedule to meet current project milestones.
Schedule recovery, also called “least cost expediting”, “project compression”, or “time-cost tradeoff”, is simply an investment in direct costs (labor, materials, equipment, and subcontractors) to reduce durations and indirect costs (project staff, trailers, trucks, office equipment, and/or temporary utilities).
During project development, a normal duration is the amount of time required to finish the project or activity under regular conditions without added delay or acceleration. Moreover, a normal cost is the cost of a project or activity that is performed within that normal duration. The activities that make up a project schedule are supposed to be most efficient, as it relates to direct costs, at their normal cost and duration, and would be used in estimating and schedule baselining.
As we discussed in our previous article on Re-Baselining, the post-pandemic economy and construction project must adjust to a new normal. Part of the re-baselining process includes re-estimating the normal duration for activities under the new economic and project safety conditions. For Recovery, we’re going to take a step further, evaluating the trade-off of cost and efficiencies for time; i.e. how much time (duration) can we buy for the least amount of money (direct cost)?
Typically, direct costs for an activity increase non-linearly as duration decreases; or said a different way, the more you accelerate, the more costly it gets. Whereas, indirect costs generally increase and decrease linearly with duration (though there all always exceptions). Using this understanding of the relationship between costs and time, here are some recommended steps, considerations, and limitations for recovering the project schedule.
Schedule Recovery Steps
1 | Identify Critical and near-Critical Paths
The first step in schedule recovery is to identify the critical path and any near critical paths, i.e. activities with the lowest float in the project schedule. The only way to shorten the overall project duration is to shorten the critical path. Often, shortening the critical path will make a near-critical path the new critical path. For this reason, schedule recovery is an iterative process.
2 | Identify Driving Constraints
Before focusing on how to reduce the schedule through reworking job logic or reducing activity durations, we must identify the path’s driving constraints and view them through a lens of project acceleration. These constraints may include:
- Adverse Weather – if weather calendars are used to define activity work windows, consider taking a closer look at specific seasonal weather predictions to determine if the weather constraints built into the schedule could be less restrictive.
- Equipment Availability – if a major piece of equipment, such as a tower crane, directly influences productivity, consider the physical constraints for adding more equipment. (later we’ll discuss the cost)
- Labor Availability – recent economic growth (before COVID-19) reduced the availability of labor, and especially skilled labor, in the market. Before we can consider the cost of adding more resources, we need to know if they are even available.
- Material Availability – a common approach to acceleration is to pay a premium for early material delivery. With the pandemic affecting all points of the supply chain, it is important to consult material suppliers and vendors to determine if early fabrication and delivery is possible.
- Business Processes – the impact of business processes, such as RFI review, change directives, and inspection coordination, on the ability to accelerate schedule is often overlooked. Collaboration between the owner and contractor is a necessity to recover schedule.
- Contract Imposed Constraints – the contract may impose constraints on the project that can be re-examined. For example: in locations where traffic flows are way below normal, municipalities are allowing lane takes, extended closure hours, or full closures where previous traffic flows did not allow such opportunities. Construction in a busy downtown area or project where business operations must continue can look at improved access and parking
3 | Re-Study Job Logic
In our previous post, Re-Baselining with Uncertainty, we emphasized the need to Re-Study the project plan to understand how best to prosecute the remaining work and the driving assumptions in the “new normal”. We follow that same approach in planning schedule recovery, but from a lens of acceleration. Take the time to engage the project delivery team in a brainstorming session to draw out innovative approaches to shorten the project schedule by adjusting job logic and activity sequencing. Here some examples of re-working job logic:
- Smart Relationships– in general, scheduling professionals and schedule specifications emphasize that most activity relationships in a project schedule should be Finish-to-Start (FS). However, take a closer look at how you may perform critical activities in parallel rather than in series, where Start-to-Start (SS) and/or Finish-to-Finish (FF) logic may more accurately reflect the relationships of activities.
- Activity Detail – the level of detail of activities in a schedule may influence the critical path. Specifically, a schedule activity may summarize multiple “steps” of a short (or long) process, like FRPS (Form, Rebar, Pour, Strip). There may be situations where only one or two of the steps are critical. Consider sub-dividing activities into critical and non-critical steps. This will improve the accuracy of the critical path and allow us to focus on what activities need to be shortened to gain additional time.
4 | Identify Activities to Shorten
After localized re-workings of job logic to shorten the critical path, the next step is to identify which activity durations could be reduced, along the path. Categorize which activities are driven by resources (direct costs) that could be adjusted, based on the evaluation of driving constraints in Step 2. Here are some common examples of ways to shorten activity durations, and their limitations.
- Longer Shifts: one of the most common ways to get more done in less days is to work more hours each day. However, don’t commit to this solution too quickly. Overtime comes at a premium cost and research shows that extending shifts leads to less productivity per hour especially when applied over long durations. This can be a significant cost increase with a quickly diminishing benefit.
- Additional Crews/Subcontracting: If available, adding crews or subcontracting to add support, may shorten durations by increasing potential productivity per day. However, additional crews can lead to site congestion, less efficiency, and more oversight. And, a congested site may not be allowed under new COVID19-related safety requirements.
- Additional Shifts: Adding a swing shift, again, may increase productivity per day. Be mindful, additional shifts can lead to communication problems between shifts and additional resource needs; for example, lighting to work at night.
- More Equipment: consider adding equipment where it significantly influences activity durations after evaluating the cost increases and physical constraints of the project site.
- Expedited Material Delivery: if vendors have the capability, paying a premium to expedite critical material deliveries can eliminate third-party influences on the critical path. Ideally, it is easiest to shorten the critical path when you have control over its influences.
5 | Assign Cost Reduction Rates
After identifying which activities can be shortened by adding resources, the next step is to calculate a cost reduction rate for each potential acceleration method. The goal is to determine the additional cost per day of schedule reduction. For example, if additional crews or shifts are added to increase daily productivity in order to shorten an activity duration, calculate the cost premium per day saved. Remember, these rates typically increase for additional days recovered because there are diminishing returns of productivity with added resources. The normal cost and duration of the baseline (or re-baselined) conditions was the most efficient investment of direct costs. Adding resources reduces cost efficiency, often making activity durations shorter at an increasing premium.
6 | Evaluate and Iterate
Lastly, and we cannot emphasize this enough, schedule recovery calculation is an iterative process of short-interval reductions. Starting with the least expensive cost rate reduction, shorten activity durations by, at most, the amount of total float in the next most critical path. If a near-critical path has 5 days of total float, reduce activity durations in order of least cost, up to 5 days—this is the logical limit of this time reduction step.
As reductions to the critical path lead to new or concurrent critical paths, re-compute the cost reduction rates, keeping in mind that there will be physical and cost limits to reducing activity durations and logical limits to accelerating a network. Keep in mind that the more we accelerate, the fewer acceleration options are available and the more expensive the options will be. The time-cost trade-off should be evaluated collaboratively among the project stakeholders.
Schedule Recovery is not just a mathematical exercise of optimizing cost increases with time reductions, because there are always more influences and probabilities of change in the real world than can be effectively modeled in schedule or computer software. The collective insight and understanding of challenges, risk, and options must include participation and buy-in from the entire project team. The owner, subcontractors, third parties, and project stakeholders must be leveraged to qualify the computational results. For example, an evaluation of least cost reduction may indicate an activity in the future may yield the most benefit; however, it is not certain if that activity will be on the critical path when it actually occurs. In this case, project managers may elect a more expensive schedule acceleration method in the near term, adding more ability to manage recovery for a longer period and avoiding the risk of the critical path changing as the project progress. This may be especially true if you are using a rolling-wave scheduling approach in the response to uncertainty in the post-COVID19 environment.
Next Step: Capture the Impacts
So far, our series has focused on how to understand, minimize, and mitigate the schedule impacts related to COVID19. At some point, either as projects complete or perhaps for some projects to resume, it will be important to capture all pandemic-related impacts and cumulative effects. The next article in our series will focus on schedule analysis methods to best calculate and communicate project impacts.