Construction Scheduling. What Schedule Reports do you Need? (For Owners).

Do you receive a truckload of schedule reports each month from the contractor?

Do you actually look at or use them all?

Do you know there are many ways of looking at the schedule to be able to review progress, planned work, work that is slipping, or work that is Near Critical?

There are all kinds of reports the contractor can provide. But, it’s best if they know what you will need before they develop the Baseline Project Schedule.

When the contractor develops the schedule, they create groups of activity codes which they assign to activities to be able to filter, sort, and group activities in various ways.

They can assign phase, trade or responsibility, area, work type and many other code assignments.

The CPM schedule can be presented is a number of ways, but typically, we see an xer file, a schedule narrative, and a group of “layouts” in pdf format.

As the owner, you need to know what “layouts” to ask for!

Your specifications should at a minimum require a Critical Path layout with the Critical Path set to equal the Longest Path. I like to show the activity ID, Description, Physical and Duration Complete, Original, Remaining and AT Completion duration columns. Also, the Start, Finish, and Total Float columns. I like to group this by the project and sort on Start and then Finish Dates. This provides the “waterfall” view of the Critical Path. With the At Completion Duration column shown, I can see if there is any delay to any in-progress activities driving the Critical Path.

Your specifications should also at a minimum require a Total Float layout. I like to set this up to be grouped by the project, sorted on Total Float and then Start and then Finish. I show the same columns as I do for the Critical Path layout above. This provides a series of “waterfalls” based on Total Float values. For projects with multiple activity calendars, we cannot rely on the Total Float value to provide an accurate representation of the Near Critical Path(s) and subsequent network paths. But, it is very useful if you keep in mind what activity calendar the types of activities you are looking at typically have assigned. Knowing another network path is only a few days away from being Critical is, well, critical.

The classic layout grouped by WBS or some sort of activity coding is typical. This is the layout you get which shows the project phasing and deliverables broken down with the supporting activities. This is a necessary layout and is almost always provided by the contractor.

There are ways to format a layout to show activities taking longer than planned, not starting or finishing as planned, and planned to start or be underway in the next few weeks. These layouts are all helpful to the owner and the contractor.

Feel free to ask me about layouts I typically use. I’m happy to explain what I use and why.

As  Planning and Schedule Professionals, we need to provide the Project Team with the “tools” they need to manage the project. The owner needs to know what presentations to require. We can help them.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. The Reality of a Project Schedule, (For Owners).

Do contractors and project owners view the project schedule differently?

Most of the time? You bet!

The contractor develops the schedule because the contract specifications require a project schedule or because they need a plan to manage the project execution or both. Does the contractor need the same degree of detail or planning as the project owner? Probably more.

The project owner wants the project schedule as assurance from the contractor that they have a plan and can execute the project. They also need the schedule to plan their own activities for the project and plan internal activities which may be separate from the project.

Most projects now require a CPM schedule. This forces the contractor to develop more detailed logic, with specific calendars. They cannot get by with a simple bar (Gantt) chart type of a schedule which simply lists the activities in the planned sequence. The contractor must develop a complex organization of finite activities with associated logic, calendars, constraints and best practices.

The project owner benefits from this, they can have a higher level of confidence in the schedule!

Or can they?

When you plan the project by breaking down the deliverables, verifying resources availability, acknowledging internal and external constraints, and planning the basic phasing and sequencing if the work, the required project completion date is a facet of the planning, but not the driver. We simply plan how we will schedule the project.

When we sequence the deliverables and add the supporting activities, based on our planning effort, we often find we will not finish the project by the contract completion date, as required.

We then consider adding resources to shorten activity durations and/or sequencing some work to run concurrently. We do this by attacking the current Longest Path, iteratively as the Longest Path keeps shifting until we have a schedule that meets the contract completion requirements.

As the project owner, you generally do not know about this exercise. You do not realize how much schedule risk has been added to the project. For larger and more sophisticated projects or owners, the use of risk management for cost, scope, and schedule is common. But, for many medium and some larger projects, there are not resources available for risk assessment and management.

For these projects, the owner believes the contractor can execute the project as planned. Often, the contractor is anxious and understands there is the additional risk and has analyzed the risk and provided a mitigation plan. However, the risk remains.

Any impact to the project schedule Critical or Near Critical Path can derail the project. There simply isn’t schedule contingency available to absorb any impact. Many owners believe the contractor has built-in contingency, just as they believe the contractor has a cost contingency. Usually, they have a cost contingency, but often it is negligible. They bid the project to win the project and keeping the contingency slim is part of winning….

Seldom is there any real schedule contingency. Contractors must address even slight impacts to the execution or sequencing of work. Owners believe the contractor should anticipate these and absorb them. It is all contractors can do to mitigate their own impact issues, much less absorb owner impacts.

How can we, as Planning and Schedule Professionals help?

I can only speak for myself…

When providing owner’s schedule oversight and management support, I try to identify the types of items in the schedule which would prevent the project team from using the schedule to accurately forecast and manage the work. It is in the best interest of all parties if the schedule is valid for use. Often, the contractors disagree and push back, but for the benefit of the project as a whole, we have to force the use of solid, valid CPM schedules.

Unfortunately, and far too often, the contract schedule requirements do not provide the support necessary to force the quality of schedule we need…. So, we do the best we can…

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Actual Date(s) Progress Update Information for Owners.

In my previous post, I touched on some of the important progress update items we review and analyze.

I will now discuss the process for Actual Start and Finish Dates and partial progress of work in progress. I will not hit this too hard as most everyone understands this process and the process varies from industry to industry. But the basics are very similar.

When the project is large, or smaller, and there is a full-time Owner’s Scheduler on the project, the Owner’s scheduler can periodically walk the project with various team members to validate Actual Start and Finish Dates. More often, for me as a Schedule Consultant, I rely on that verification by the Owner’s Representative on site. It’s a standard part of developing the “pencil copy” pay application or draft invoice.

However, what often happens is the review is overly concerned with determining what percent complete work in progress is. While this is important, getting the accurate Actual Start and Finish Dates is critical as well.

When working with the contractor to determine the progress for a performance period, we typically walk the project and either agree or disagree with their assessment. We should also be reviewing our daily reports for the actual dates.

Back when I was an inspector, I liked to keep a copy of the three week look ahead schedule with me so I could jot down an actual date when I came across it in the field. This allowed me to write it and forget it so I could focus on other matters. It was also very helpful when reviewing the “pencil copy” pay application.

Coming to the agreement of percent complete for work in progress was not too difficult, but getting the expected Finish Date was. We really had to discuss the performance of that work individually, decide if the progress was improving, had some delay or was simply not important enough today to throw resources at. In any event, the expected Finish Date for an in-progress activity is crucial to determining what the status is and how the project proceeds from this update. It needs to be as accurate as possible. If we bag it, we can force it Critical or Near Critical resulting in an erroneous shift in resources. If we only rely on the best-case scenario, we may not allow the focus necessary to recover this next update period.

The owner really needs to have someone in the field, daily, keeping up with the actual and planned progress. The rest of the schedule progress update is based on this data. Any revisions and planning done by the contractor to recover time lost or shift resources to maintain schedule are dependent on this information being accurate. Any potential delay or change order issues are also affected by this information. This information sets the status of the project at the time of the progress update. This determines the current Critical and Near Critical Path(s).

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. General Progress Update Information for Owners.

When we develop the Baseline CPM Schedule for a construction project, we know we will need to use the Baseline CPM Schedule to measure performance during project execution. With this in mind, we work with the contractor to help get an acceptable Baseline CPM Schedule for the project. That’s usually a tough task, many contractors don’t believe it necessary or simply do not want to follow parts of the schedule specifications or best practice for schedule development. But, we usually end up with a schedule we can use to track progress and manage the work and changes.

I often see problems on projects once we start getting schedule updates from the contractor. Some owners believe the Original Baseline CPM Schedule is the most important schedule we measure against. This is partly true, we do need to reference the original plan as we go. But, after the first couple of progress updates, the remaining plan to execute the project has changed. Sometimes there have been major change orders, delays or resequencing of work. When this happens, we need to revise the Baseline CPM Schedule. Most of us understand the need to re-Baseline.

What I find many do not understand is how important it is to keep the progress updates valid. The owner really needs to be able to validate Actual Start and Finish dates in addition to agreeing with the partial progress reported for work in progress. These three items determine the as-built schedule condition and establish the plan to continue with project execution.

That is what the owner can see in the Gantt Chart pdf.

What about what goes on behind the scenes when the contractor is applying the update data? Who is watching to see if logic is changed? If calendars are adjusted? If resources are revised?

There are many things the owner cannot verify or validate that absolutely need to be confirmed. This is where the Owner’s review and oversight of the scheduling process come in to play.

With each progress update submitted by the contractor, we look at several areas to ensure the schedule integrity is maintained.

First, we simply make sure the network logic is still complete. This also includes verifying there are not any open ends such as a Start-to-Start, SS successor relationship which leaves the finish of an activity open. We run diagnostics to uncover what logic, durations, calendars, and activity additions/deletions have been revised and analyze this data to understand what the changes actually do to the schedule. We need to determine if the contractor’s revisions of a few relationships from Finish-to-Start, FS to SS shortens a network path enough to shift the Critical Path. It may be unintentional, but we must still review and validate. Sometimes these relationship revisions are done to correct Out-of-Sequence, OOS logic, sometimes it is done to recover lost time and bring the schedule completion back.

We look for calendar changes which often affect Total Float and the Network Path. We look at changes to durations and flag lack of progress for activities not projecting to complete as planned. This needs to be investigated to determine the causation. We verify Out-of-Sequence Logic has been corrected to keep invalid relationships from driving remaining logic and dates.

We analyze the actual progress of the project as a whole and also look at the Critical Path work performance as well as Near Critical Path(s) work performance. Doing work on the Critical Path is important. Doing work on the Near Critical Path(s) is also important. However, if work not yet Near Critical is not executed aggressively, the result in the stacking of work adds unachievable resource demand to the remaining scheduled work. This often drives the search for the “miracle” towards the end of the project….

We have to monitor all this, and you really can’t get that kind of insight from the Gantt Chart pdf.

We have to validate the progress update schedule. After all, the revisions to pull back the schedule and make minor sequencing changes have obviously resulted in logic or other changes. We need to verify that the schedule still meets the schedule specifications and best practices. Each progress update becomes the basis for any time impacts for the next performance period. The schedule update has to be valid.

I will elaborate more on how we accomplish many of these tasks in future posts.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Schedule Revisions and the Reality Check.

When we finish updating Actual Progress for the Schedule Update, (See previous post), how do we revise the schedule to maintain the contract completion date or whatever period of performance is required?

How do we get the Project Schedule back on-track?

More often than not, the Schedule Update models actual performance which does not support an on-time project completion. Work slips, production isn’t what was planned, deliveries are late…..

The Project Team usually has to make Schedule Revisions to “recover” the lost time. This is sometimes called “crashing” the schedule.

This is an exercise based in future failure.

When most schedules are developed, they are already overly optimistic because the Project Team had to “crash” the schedule to even create the Project Baseline Schedule. Once the work starts and progress slips, the work starts to stack. Even if the Critical path work is completed sufficiently to maintain the Critical Path, all the other work activities have to maintain or beat their dates. If not, that work pushes out and soon stacks up to double the resources necessary to complete the work later. If we couldn’t complete the work as-planned, why will we be able to complete it later, when we have fewer resources to work with? What is going to change?

Back to the Schedule Revision process. The process is basically looking at the current Critical Path and deciding which activity duration can be shortened cost-effectively or which logic for sequential activities can be changed to have them run concurrently, with a slight bit of lag time. Then the schedule is calculated again and this process is repeated until the schedule is “on-track”.

Unfortunately, this is also when contractors are pressured into completing work in less time than they may have budgeted or have the resources to support. But, this is often exactly what happens.

Now we have a schedule for the remaining project work which is most certainly impossible to execute. Sure, the owner will issue change orders which may provide some concurrent delay the contractor can attach their lack of progress to. But most likely, there will not be enough changes to cover all the time lost.

It is my opinion that the best thing the Project Team can do, is establish the most realistic expected Finish Date for incomplete work. This also applies to establishing the most realistic delay (lag) in concurrent work planned to recover time. If these revisions are not realistic, the contractor can’t support the shortened duration or additional resources necessary, then we are just kicking the proverbial can down the road.

We should, as Schedule Professionals, provide the “reality” of the project performance and the realistic plan to execute the remaining project work and let the Project Stakeholders know sooner than later that the project cannot, under the current cost or resource constraints maintain the contract completion date or period of performance.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Progress Updates and Incomplete Work.

When we update Actual Progress for the Schedule update, how do we report the incomplete activities? How do we report the progress for the work, (activities) currently in progress?

We know how to report the completed work.

More often than not, there are many activities which may have Actual Start Dates in the previous Update Period. There are also activities which will have Actual Start Dates and Finish Dates in this Progress Update. There will also be activities which will not have Actual Finish Dates. The way we report the Actual Progress for these activities is crucial to maintaining the schedule validity.

The Project Team has to decide just how much of the “work” represented by the activity is complete. What percentage of the work is complete…. This should be a measure of quantity completed.

Too often, we see the Duration Percent Complete set as the Progress Percent Complete. This is not the best method of reporting the Actual Progress.

If the Duration Percent Complete is used to report the Actual Progress, the schedule is not going to be valid. Setting the Duration Percent Complete to a specific value results in the program calculating the Remaining Duration. This, in turn, establishes the scheduled Finish Date for that activity. This is the problem. The scheduled Finish Date for an incomplete activity should be set by the Project Team as the date they expect the work for that activity to actually finish. Unless this scheduled Finish Date is used, and the successor activities driven by the remaining duration and logic for the network string are allowed to calculate the new scheduled dates, the schedule is not valid.

Using Duration Percent Complete does not, in most cases, represent the actual schedule progress and accurately model the remaining plan to execute the project.

A better method to report Actual Progress is the use of Physical Percent Complete. This value is based on the actual work in place. The Duration Percent Complete should be the result of setting the scheduled Finish Date or Remaining Duration based on Project Team input. This allows us to have the value of work in place and the value of the time used to complete this work in place. We can then easily see if we are meeting the required productivity rate for this work activity.

The next step, after entering all the Actual Dates and Scheduled Finish Dates, (or adjusting Remaining Durations for in-progress work), is to “schedule” or calculate the project schedule. We should then look at the Out-of-Sequence, OOS logic and make corrections.

I believe in correcting all the OOS logic each update. Many do not consider this necessary and others consider it only necessary for activities on the Critical or Near Critical Paths. Some Schedule Specifications or Requirements address this issue, but most do not. I consider it a best practice for keeping the schedule valid for the as-built progress and do not like the idea of the OOS logic driving future dates and logic, which can happen.

Using the Physical Percent Complete for reporting Actual Work in Place, letting the Duration Percent Compete report the actual Activity Duration consumed, and correcting the OOS logic is the first part of the Progress Update process.

This allows us to maintain the schedule as a valid tool for planning the remaining work from the Data Date forward. If the Progress Update results in a late Finish Date for the project, then we have some work to do. This is, more often than not, the case. We can make adjustments to the plan to complete the remaining work through Schedule Revisions. This issue is a subject for another post.

It is my opinion that the best thing the Project Team can do is establish the most realistic Progress Update possible, each Update Period. If we don’t know where the project actually is, how can we drive the project to a successful completion? If the Progress Update is not valid, the Critical Path and Near Critical Path(s) are most likely not valid. How then, can a Project Team manage the Critical work? How can the Project Team identify and address work which is actually lagging?

We should, as Schedule Professionals, provide the “reality” of the project performance.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Activity Durations and Unicorns.

When the schedule is developed, (after the project has been broken down and organized into the WBS and the activities have been developed to support the deliverables), how do we determine the duration for each activity?

How do we accurately determine the work period for each activity?

There are several ways this task is approached. Some are better than others….

I believe we can all agree that knowing the required work quantity and production rate per day is the best input we can have to accurately calculate the duration. How often do we actually have that much detail?

More often, the project team determines the durations based on their “feel” for how long the work will take based on similar work from the last few projects. This is not necessarily a bad thing. This is historical data and is very useful.

The problem is that we tend to be optimistic. The larger the piece of work is, the more difficult it is to accurately determine the duration, by “feel”.

Typically, the activities are all developed based on input from the project team, the constrained finish date is applied and then the schedule is “calculated”. Usually, we do not make the required finish date.

Now we start crashing the schedule to pull the finish date back.

We’ve all seen videos of buildings constructed in a week and other supernatural feats. So, it stands to reason that we can build anything within any timeframe, right? If the owner wants the project by the date in the contract, we have to crunch the schedule until it shows we can deliver on time.

As we know, a very high percentage of projects do not finish on time. This often leads to claims and poor performance reviews.

Is it possible that we set our projects up for failure at the very beginning? Do we assume we can provide a finished project within the contract duration just because the owner has specified the period of performance?

If the schedule is constructed using “most likely” durations for all activities with reasonable logic and the project is then constrained to finish on whatever date that produces, there is still a good chance the project will finish late. It could finish early, but that seldom seems to happen.

If the durations are based on pessimistic durations, the project will still tend to use the time allowed leaving little room for problems towards the end of the project.

If we place a contingency activity at the end of the project, we can work towards an early completion hoping we magically finish on or ahead of time.

Or, we can put the effort into building very detailed schedules with solid logic and durations and then execute the projects per the schedules, as well as possible.

Any way you slice it, a poor schedule does not work. An aggressive schedule is not realistic and will soon fall apart, a pessimistic schedule will also fail due to a lack of aggression to complete work.

A detailed schedule, with input from all team members, does not guarantee success, but it does provide a realistic path to get there. It is up to the project team to execute based on the plan. But they can’t do that without a solid schedule.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Schedule Progress Updates and the PM.

The Project Manager is responsible for many deliverables and processes for the project.

Scope, cost, communication, time, and quality.

Part of managing the cost and time is the coordination of work and subsequent reporting of work completed.

Many projects base the periodic invoicing on the percentage of work completed for that period. Others use Milestones for payments. There are other methods as well. For this post, we will work with the percentage of work based on the progress completed for each activity.

Correct updating and reporting of the schedule progress is a large part of the process. And invoicing is a big deal!

How does the PM report on the work completed? Should they use the percentage of time used for the activity? Should they use the percentage of actual cost expended? Should they use the percentage of work in place?

Depending on the contract type, there are options. Personally, I prefer to base the invoicing on the percentage of physical work in place. After all, why would an owner pay for your time or actual expenses, unless the work is T&M?

To update the progress based on physical work in place, you simply manually assign the physical percent complete for work in progress and set the scheduled finish date based on the planned remaining duration or finish date. It is that simple. The cost can be calculated in the software program or in a spreadsheet.

One of the useful things about using physical percent complete and letting the remaining duration or scheduled finish determine the duration percent complete is the variance between percent complete this creates.

If you have completed 50% of the work and the remaining duration or scheduled finish date results in a duration percent complete of 70%, it is obviously taking longer to complete this work than planned.

Perhaps this indicates a learning curve for this work. Perhaps there was a delay in material delivery once the activity started. There could be many reasons. But, the PM should know the reason and they cannot know to find out if they do not have an indicator that there is a problem.

Many people just assign the percent complete as duration percent complete and let the program assign the scheduled finish date based on the original duration and remaining duration values. This is a problem for several reasons. First, this method models the time used and remaining, not the work in place. Second, the scheduled finish date is based on the assumption that the productivity rate is as planned. Seldom is this correct. Finally, letting the duration percent complete value calculate the scheduled finish date does not model the remaining work for the project accurately. Basing an invoice on this method will result in inaccurate invoices for work in place and a schedule that is not valid for the remaining work. It’s a good practice to be accurate in these areas.

Although it is not often used in the typical layouts I see, displaying the “At Completion Duration” column in the layout also provides a quick flag for activities that are exceeding the original duration. Most layouts display the “Original Duration” and the “Remaining Duration” columns. But this doesn’t really alert the PM to a potential problem with activity progress and productivity.

I’m a big supporter of using physical percent complete for work in place and setting the scheduled finish date for work in progress by revising the remaining duration value or setting the date based on field input. I also like to display the “At Completion Duration” column in my layouts. I think providing the Project Manager with as many tools as we can to help them make intelligent decisions for managing the work is our primary function.

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Why Work When We Can Wait?

When the baseline schedule is developed correctly, the schedule logic is complete, activity durations and activity calendars are assigned, resources with cost may have been assigned, and activity coding is developed and assigned.

All of this creates the schedule network. This schedule network is made up of many sequences (logic paths) of activities.

Once the schedule is calculated (forward and backward pass), the schedule network will provide scheduled dates for activities not yet complete. At any given time, a small percentage of activities will have scheduled dates which show they should be starting and completing within a defined period of time, (say this week or this month…).

Some of these activities will be on the Critical Path. Some will be on the Near Critical Path(s). Some will have Total Float values which allow them to remain unstarted or incomplete for a period of time dependent on the Total Float value.

We all understand that the work on the Critical Path needs to be driven at all times. We understand that work on the Near Critical Path(s) also needs to be driven so it does not lag and shift to the Critical Path.

What about the activities with Total Float values which allow the work for these activities to lag without affecting the Project Completion Date?

Should this work be executed when it is convenient? Should this work be pushed out until it is on the Near Critical path(s)?

Part of the CPM Schedule development process was the analysis of the resources for activities to verify a specific resource did not have more activities scheduled to be underway than the resource could support. This can be done manually or using software programs that run Monte Carlo analysis for resource leveling.

That said, why would we want to allow work to slip? It is my opinion that any work which can logically be executed should be executed as long as the resources required do not exceed the planned resources for that time period. But, sometimes it is better to add resources to execute the work for a variety of reasons.

By allowing work to slip, only because there is no schedule driven reason to execute the work at that time, the work will eventually push out until the activities with a specific resource assignment are stacked resulting in an overallocation condition which forces some of this work to push out due to lack of resources. Whether the schedule is resource loaded or not, we all know that a subcontractor can only do so much with the forces they have on the project at any given time.

Allowing the work to slip also increases the risk of a late completion due to the potential of shifting of the Critical and Near Critical Path(s).

Finally, allowing work to slip has a negative impact on the schedule cost curve and distribution plan. The project may be reporting an on-time completion and the Critical Path may have an acceptable Total Float value, but if work is pushing out, the completed values will produce an unacceptable Cost Variance (CV), Cost Performance Index (CPI), Schedule Variance (SV), and Schedule Performance Index (SPI).

Projects with poor Earned Value metrics seldom recover.

I say, if the work is available to be executed, the resources are available, and executing the work will not lessen the focus on the Critical and Near Critical Path(s), it is wise to work in where you can, when you can.

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. What are the Critical and Near Critical Paths? Why do we care?

When the schedule is developed, the schedule logic should be complete. All activities should have at least one predecessor and one successor, with the exception of the first and last activities for the schedule.

If this is done, the combination of activity durations, activity calendar assignments, and schedule logic create the CPM schedule network. This CPM schedule network is made up of many sequences (logic paths) of activities.

In simple terms, the longest continual path from the project start to the end of the project or the next hard constraint establishes the Critical (Longest) Path.

The Total Float values are a just the product of the forward and backward pass through the CPM schedule network. Just because the Total Float value is zero does not make the activity critical.

However, the Total Float values are important. If the Critical Path has a Total Float value of zero, then the Near Critical Path activities will most likely have a Total Float value very close to zero. I say most likely because the activity calendar assignment has an impact on the Total Float values. But often, this is a simple rule of thumb for determining the Near Critical Path. I like to keep an eye on work that is on the Critical Path first and then also pay attention to work that falls on the Near Critical Path(s) within one or two weeks of the Critical Path for large projects and a few days for small projects.

It’s not unusual for the PM and Superintendent to focus on work on the Critical Path and not pay enough attention to work on the Near Critical Path(s) and then have the Critical Path shift because a lack of progress for the Near Critical Path work took over the Critical Path.

This is just one reason complete logic, calendar definition and assignment, and limiting constraints are important when developing a baseline CPM schedule. If you scatter constraints throughout the schedule, you will not have a true Critical Path for the project. Without complete logic, you do not have the means to accurately complete the forward and backward pass that establishes the CPM schedule network scheduled dates and Total Float values. Without calendar definition and proper assignment to activities, durations will be erroneous and this will ultimately produce a false schedule network.

I know many of you can offer additional comments and recommendations. I welcome your comments and input. My goal, as always, is to help our industry and help the projects we support….

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP