Construction Project Scheduling – Page 2 – Construction and Schedule Management Services

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. 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

Construction Scheduling. What Data Columns Should be Displayed?

Do you ever look at a schedule pdf and wish you had access to more information? Know what the percent complete actually is? What produces the Total Float value?

Would you like to be able to see what is most important to you, as a PM? As an Owner? As a subcontractor?

When your contractor develops the project baseline schedule, they develop a few simple layouts for the project. (Or they should…) We typically set up a Classic Layout with Start, Finish, Percent Complete, Duration….

But we can also set up specific layouts for use by different team members.

However, often what you find in a progress or owner’s meeting is the two or three week look ahead schedule with the Activity ID, Name, % Complete, Duration, and Start & Finish dates. This doesn’t really offer much useful information.

I like to develop several layouts.

One layout that I use has the ID, Name, Physical % Complete, Duration % Complete, Original Duration, Remaining duration, At Completion duration, Start, Finish, and Total Float value. I can use these columns to see variances in duration usage and physical work completion. This quickly alerts me to production issues or potential delays. (It is possible to target previous updates and show actual variance values for duration, start and finish dates).

I also like to produce a simple progress update worksheet for the superintendent and field staff to use for keeping track of actual start and finish dates. They can keep these at their desk and mark off the dates as they happen each day. At the end of the month, all they have to do is add the physical % complete for the work still in progress. It’s just that simple. I provide a column for them to enter the date they now expect to finish the in-progress work. Using this expected finish date, we revise the remaining duration and the At Completion duration. This provides us with the Duration % Complete and the At Completion Duration variances which allow us to spot trends and take corrective action quickly.

Those are very simple layouts.

There are options for the Project Team. Let the scheduler show you what they can produce and work with them to find the right layouts with the right data columns that work for you. It will make managing work much easier for everyone.

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

Construction Scheduling. Let Durations Help You.

How can you use the Activity Duration value to help you manage your schedule?

Simple, just look at all the columns and do some math in your head.

When your contractor develops the project baseline schedule, they develop the Original Duration for each activity. How they develop the durations is a subject for another post. But let’s assume they have used historical data, input from subcontractors, calculated productivity and quantities, or some method of developing an accurate value for the each Activity’s Original Duration.

Most Schedule Presentations (Gantt Chart pdf’s) have the activity names, dates, a percent complete and a duration for each activity shown in columns. Then there are the magical bars to the right. Sometimes there are even relationship (logic) lines drawn from activity to activity so you know what drives what, right? Can you actually read it? Doubtful…. Anyway, let’s focus on the duration columns.

If you’re looking at a Schedule Presentation from a Primavera P6 schedule, there are options for which duration columns you can see. Almost everyone uses the Original Duration column. Most of us use the Remaining duration column. That’s all we need to know, correct?

Not really, there is a column that shows the At Completion Duration. This is not seen in presentations that often, probably because we want more room for the magic bars and lines… But this is an important column to be able to see when reviewing a Schedule Presentation pdf.

If you have an Original Duration of 5 days (Work Days or Calendar Days depends on the Calendar. This is a subject for another post), and a Remaining Duration of 3 days and the percent complete (whether it is Physical, Duration, Activity, Performance, or Cost or another type is a subject for another post), is 50%, things are looking good, right?

Not always. If you look at the At Completion Duration, you may find that while the Original Duration is 5 and the Remaining duration is 3. But the At Completion Duration could be 35 or any other value if the activity finish date is riding the Data Date. This can happen depending on the settings used to manage the schedule. Unless you actually look at the dates and do some calculations in your head while reviewing the schedule, when you don’t have the At Completion duration column to use, you may not see the slippage.

Ask your contractor to display the At Completion Duration column for their Progress Meeting Look Ahead Schedules and any other pdf submission. It’s worth the trade off with the magic bars and lines!

Knowing what was planned, what is remaining and what the time impact of activity progress slippage is can save you some trouble.

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

Construction Scheduling. Use of Relationship.

When your contractor develops the project baseline schedule, do they use many Start-to-Start (SS) or Finish-to-Finish (FF) relationships? Do you know?

A relationship determines how the successor activity will start or finish relative to the predecessor activity. The most common relationship is the Finish-to-Start (FS) relationship. The scheduled finish date for Activity A determines the scheduled start date for activity B. Unless a lag is assigned, this is simple. (See previous post).

However, often the schedule model requires the use of SS and/or FF relationships. If the activities will actually run concurrent and the activities are broken down to the level of detail necessary to plan and manage the work, this is acceptable. If the relationship includes the assignment of a lag, it may still be acceptable but this relationship should be reviewed and agreed to by all parties.

The problem arises when the series of work activities is developed with SS relationships and there are not any successors to the finish of these activities. These are essentially open ended relationships which means the activity could not finish and still not affect the schedule. This may indicate the work is not developed to enough detail to allow Finish-to-Start (FS) relationships to drive the work. Or the addition of work driven by the activity was missed during schedule development. If this work happens to fall on the Longest Path, this path is now driven only by the start of work for each activity, not by the finish of the work for the activity. In time, these relationships may fall on the Longest Path through updates and out-of-sequence work. personally, I prefer to limit the use of SS relationships in general.

Then there are the Finish-to-Finish (FF) relationships. These force the successor’s scheduled finish date to push out to follow the predecessor’s schedule finish date. This is commonly used to close off SS relationships to model concurrent work with the finish dependency. However, often the only successor is the FF relationship. This creates an open finish, which is much like a missing successor. If the predecessor has only the finish of the concurrent activity to drive, and this relationship is a FF relationship, and the successor has no other predecessor. It effectively has no predecessor to the start of this work. If the predecessor activity has only the successor with a FF relationship, what future work does it drive?

Finally, there is the combination of relationships that create reverse logic. Activity A is a FF to Activity B. Activity C is a SS to activity B. The duration of activity B determines when activity C can be scheduled to start. The start of activity B is not driven by any other work. The finish of activity B is driven by the finish of activity A. If the duration for activity B is increased, unless the start of activity C is driven by another predecessor relationship, the start date for activity C is pulled back to schedule an earlier start. This can have unintended consequences for the schedule. We see this often when the schedule is developed using a lot of SS and FF relationships.

We won’t mention the Start-to-Finish (SF) relationship. This is extremely rare. This says that the start of a predecessor cannot start until the finish of the successor. I have only seen it used intentionally and with an acceptable reason twice. And that was to model work on a rolling wave schedule for which there was not much design detail developed. However, this relationship is sometimes used by mistake.

The SS or FF relationship, if used correctly, can allow the schedule to model the plan. It is my opinion that the use of these relationships should be kept to the absolute minimum and be only used to model actual planned concurrent work which is broken down into the level of detail necessary to plan and control the work.

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

Construction Scheduling. What Value do Schedule Professionals Bring to a Project Owner?

Many construction project owners have specifications for the project RFP which, at the very minimum, require a CPM schedule and a specific schedule progress update process. This tells me that they take the project schedule development and management very seriously.

But, do owners always have a schedule professional on their team? Perhaps in-house, with the CMa contractor, or at least as a third-party consultant?

More often than you would think, they do not.

Maybe it’s budget constraints, lack of staffing, or bad experiences with project scheduling in general, but some owners choose to receive a simple schedule Gantt Chart pdf from the contractor and call themselves managing the project schedule.

I can understand this, to a point. Some projects are simple enough and can be managed this way. Some owner-contractor relationships are strong enough that both parties trust the other will compensate them for delays or late completion.

What about the projects that really should have a schedule professional supporting the owner with schedule oversight? What value do they receive when they have that support in place?

First, they should benefit from bringing the scheduler in early, prior to issuing the RFP to review and refine the schedule specification. Many owners use the same specification over and over and have not updated to the current schedule program outputs or schedule best practices. A professional scheduler can help develop a schedule specification that will provide the requirements for the development of a quality schedule which can be used to manage the project.

Second, they can review baseline schedule submissions and verify the contractor is meeting the requirements of the schedule specifications and following best practices to produce a valid baseline schedule.

This may require multiple iterations of the development and review process, depending on the contractor’s ability and willingness to actually develop a quality schedule. But once this is accomplished, the entire project team benefits from a baseline schedule which can be trusted to provide a sound basis for change order management and work management.

That said, a schedule professional adds value to the update process as well. They review the progress update for errors in updating the schedule such as actual dates in the future and the coordination of percent complete, duration changes, calendar changes, resource changes, schedule revisions to correct out-of-sequence work and revise the contractor’s plan going forward. The schedule has to be validated each update to maintain the integrity of the schedule network.

The schedule professional also provides the owner’s analysis of delay impacts submitted by the contractor for change orders or delays by the owner. This is not possible without all of the supporting work listed above for baseline development and update validation.

What about when the contractor is not meeting the planned production rates and the scheduled activities are getting pushed back in the schedule each update without the scheduled finish date being affected? Seems like that would be obvious to the owner’s team, but often it is a slow creep of slippage that is hard to pin down. The schedule professional knows how to quantify the slippage and identify the work driving the slippage. This is handy when discussing miracle options with the contractor.

An owner can possibly manage a project without a schedule professional on their team. But, would they manage a project without a cost estimator for scope planning or change order management? What about an inspector for quality assurance? Would an owner manage a project without being able to monitor and validate the quality of the construction?

It’s tough to quantify what value a professional scheduler brings to the owner’s team, but there are definitely costs to not having one. A questionable baseline schedule, the inability to project work with confidence, and the inability to accurately quantify change order delays are only a few basic functions that would be lost.

I know many of you can offer additional comments and war stories, for all of us. 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

Construction Scheduling. Do You Manage Your Project with the Project Schedule?

Question Why would you not use the schedule to manage the project?

If you put the effort into developing a detailed CPM schedule with input from the project team members, isn’t the schedule the best road map you have?

One of the great opportunities development of the baseline schedule offers is the project team’s review and input into the analysis of the scope of work for the project.

Depending on how your company estimates and proposes on projects, the people charged with executing the project after the award of the project to your company may have had limited to no involvement or exposure to the project requirements and the basic plan to execute the project based on the proposal.

The schedule development process encourages the project team to review the requirements, understand the sequencing of the work and sometimes even uncover an opportunity to improve on the initial proposed plan.

Assuming the project team has developed a great detailed baseline CPM schedule. I can’t imagine why anyone would not use the schedule to plan and manage work. Management likes to use the schedule to track and measure performance, but I consider the project schedule to be the project team’s best tool for executing the project.

Unfortunately, I run into projects that only produced the baseline schedule because it was required. The progress updates were used for invoice backup only and no effort was put into accurately updating and correcting out-of-sequence work and revising the plan to complete the remaining work in the project. Sadly, these projects do not have a valid schedule to base change order and delay impacts on. They also do not have an accurate idea of if or when the project will complete, much less what is required to get there.

There are many reasons to develop and use a detailed CPM schedule to manage the project. I can’t think of a good reason not to.

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. Resource and Cost Loading the Schedule

person-question-300x300 Once you have the basic CPM schedule development completed and you’re ready to start resource and cost loading, do you find the schedule specifications lacking in requirements or guidance for this part of the schedule development?

Some schedule requirements simply do not require resource or cost loading. Some require the assignment of resources but do not speak to cost. Some allow simple lump sum cost loading, some require unit pricing with equipment and material costs broken out.

Whatever the case, most of us prefer the schedule be cost loaded, at least the baseline schedule. This allows us to create the performance measurement cost curve for EVMS and the early and late cost curves many of us are familiar with and most specifications require.

Each planning and schedule professional will have their own preferences for resource and cost loading the schedule.

Myself, when a lack of requirements allows, I prefer the resource and cost loading be kept simple. Unless the payment process for the project is based on unit prices and crew pricing, I avoid unit pricing with equipment and material costs broken out. I work mostly in mid-size construction projects and find that lump sum cost loading works just fine.

One thing I prefer is to keep my percent complete type set to physical and make the cost percent complete equal the physical percent complete. I find this works well if the delivery of large equipment is cost loaded and work activities are assigned cost which includes labor, equipment and basic materials. Simple to develop, manage, understand and track. Remember, this is for general construction. Road, UG infrastructure, and other linear unit driven schedules will benefit from unit pricing.

I also like to assign a resource for each subcontract, even though I lump-sum cost load. This allows a resource or cost curve for each. This helps with resource level analysis.

I believe resource and cost loading of schedules is an underserved discussion topic and our industry as a whole would benefit from learning how various industries and project types approach this process.

Hopefully, this post will help start some dialogue among us.

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. Developing trust with the Owner, for Schedule Management.

person-question-300x300 I often assist contractors with their schedule development and updates. This also includes preparing the “fragnets” for Time Impact Analysis, (TIA) or change orders. I get the impression from many owners that they do not trust the fragnet or analysis supporting the time extension request.

I worked many years on the “owner’s side” of projects. I understand the concerns most owners have. It only takes being lied to once to create a skeptic…

How do we, as professional planning and schedule consultants overcome the widespread distrust owners have, specifically when it comes to developing and supporting fragnets, TIA’s, or change orders?

I find the majority of contractors I work with to be honest & above board. They act with integrity and genuinely want to provide the best product and service they believe the owner has contracted for.

I find the majority of owners I work with believe they have provided the contractor with a good set of contract documents to work with and really do want the contractor to be successful on their project.

I believe the most important thing we can do, as professional planning and schedule consultants, is educate our clients by teaching them how the time impact “plugs” into the schedule; how the various calendars with non-work days affect the scheduled dates and total float downstream of the fragnet; how to properly manage the schedule updates and revisions to use the correct schedule to base the impact on.

If we could teach our clients the basics of change management for schedules, they might have a better understanding of what is prepared and presented, which would perhaps help in making the “negotiation” of the time impact go smoothly.

Who knows? It just might help build a little trust on the project…

What other methods have you found to help with this issue?

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