Schedule Development – Construction and Schedule Management Services

Construction Scheduling. Do you have a Schedule or a CPM Schedule?

Is what you’ve created a CPM schedule? Or is it a schedule with dates and activity bars?

Can you tell the difference?

First, CPM stands for Critical Path Method and is kind of a general term often used for Precedence Diagram Method, PDM schedule development.

Almost any schedule developed, using one the many current scheduling software programs, will be created based on the precedence diagram method. Most of the current scheduling software programs are set up for that.

Creating the WBS structure or summary bars and adding activities that model the work for the project in these programs will produce a schedule.

But is this really a useful schedule? Or is it a list of activities with dates assigned through the use of incomplete logic and date constraints? We get a list of activities with planned dates. That’s all we need, right? Isn’t that a schedule…?

Not really. That may be useful for conveying the basic plan for future work. But this is not a dynamic CPM schedule that can be used to model future work based on current progress, produce a Longest Path, or model the impact added or delayed work may have on future completion dates for the project.

I run into this a lot. A PM or someone on the project team will create a schedule and assume it is a CPM schedule. There are a few requirements to meet before a schedule can be considered a true CPM schedule.

Listed below are the minimum requirements for a CPM schedule.

Calendars.

For your schedule to be reasonably accurate, calendars need to be created to allow activities to have durations based on planned work periods. This usually requires the development and use of multiple calendars to account for various work periods such as 5-day 8-hour workweeks; 4-day 10-hour workweeks; workweeks with specific holidays set as non-workdays; anticipated non-workdays due to anticipated weather impacts….

Logic.

The only activity without a predecessor should be the first activity in the schedule. Usually NTP. The only activity without a successor should be the last activity, usually Project Complete or CCD… To be a true CPM schedule, all activity dates should be driven by the predecessor activities durations and logic. Having only all the predecessors assigned is not enough. There must be activities that are driven by the start or finish of a predecessor activity. If the activity in fact, does not drive the start of any work except the end of the project, then the successor should the last activity.

Constraints.

There are valid uses for date constraints in any schedule. However, overuse creates multiple interruptions to the forward and backward passes which determine float values. This produces snippets of paths based on the types of date constraints. Just using a constraint to set a planned start date for an activity is not a valid use of a date constraint. An interim date constraint should represent an external driving force for an activity or milestone or the contractually required date for a milestone. Limiting the use of date constraints allows the activity durations and activity relationships, (logic) to drive finish dates and produce a Longest Path to the finish of the project. This gives us the Critical Path for completion of the project.

Relationships and lags.

There valid reasons for using SS and/or FF relationships to model the planned sequencing of activities. But they should not be used in lieu of decomposing the work. Using SS and /or FF relationships should only be used to model work which will run concurrently even when the work is broken down to a reasonably small duration. Lags should not be used to model work or a waiting period. Lags are not transparent and using a lag with SS or FF relationships results in the work being modeled to start or finish based on a set time after the driving relationship has been satisfied, not on actual measurable work being complete to a specific point.

These are the most basic requirements for a CPM schedule.

The idea is to end up with a schedule that will model the impact actual progress to-date has on remaining scheduled activity dates. A CPM schedule can be used by the project team to proactively manage current schedule slippage, more accurately manage resources, and project finish dates and time-scaled cost flow.

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. Milestones and Constraints.

From time to time, I hear a project team member refer to a constraint when what they are actually referring to is a milestone.

This is really a “jargon” issue. I’ve heard people refer to a milestone with the intention of the milestone being a constraint on the project. I’ve heard people describe a project constraint as a schedule constraint.

It gets a bit confusing.

A PM may consider a required completion date of a phase of the project as a milestone. To a scheduler, this is an interim milestone and may or may not be date constrained, (Constrained with a schedule constraint assigned in the CPM schedule software program). If this milestone has a contractually required date, a scheduler may assign the appropriate date constraint. If the milestone is just for reporting purposes, the scheduler need only make sure the appropriate activities drive and are driven by the milestone activity.

A PM may refer to a project constraint, like the coordination with an owner delivery or requirement from outside of the project scope and control of the contractor. A scheduler will consider this an external constraint and may assign an appropriate date constraint. (If the date constraint would be a “start no earlier than”, I sometimes prefer to use a lag to NTP… I like to avoid the use of date constraints….).

A scheduler shouldn’t assign date constraints to every “milestone” or “constraint” referenced by the project team. The use of date constraints should be minimized and only applied when necessary.

The PM should understand that they may need to clarify when they really need a date constraint applied. The scheduler may not pick up on the requirement based on discussions among the project team.

The communication between the project team and the planner / scheduler is critical to the successful development and management of the project schedule. The different “jargon” we use can make this more difficult. We need to be aware of this and be sure to clarify when we’re unsure.

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. Including Inspection, Testing, and Commissioning Activities in the Construction CPM Schedule?

Are you including activities for the testing of equipment and systems, inspections for acceptance of systems and areas, and the commissioning of systems when you develop your baseline schedule?

People often focus on the “construction” activities when developing the schedule.

But the construction activities are only a part of the plan to execute the project. There are submittals and procurement, permits, and the closeout process.

One of the areas often overlooked is the inspection, testing, and commissioning process. There will be all kinds of inspections for the acceptance of specific work and entire systems. While it’s not a good idea to try and add all the specific installation inspections and tests that occur on an almost daily basis. We should include the inspections and tests for systems.

It makes sense to include an inspection and pre-operational test for the fire alarm system, fire suppression system, elevator, security system, electrical system, and mechanical system for a specific area or structure. There may be more for your specific project… Unfortunately, I see schedules that only have an activity at the end of the schedule named “commission” or “punch list inspection”. These activities are vague and can’t really address the need to test the systems individually and as necessary, in conjunction with each other. (Think Fire Alarm and Elevator or Fire Alarm and HVAC system zone controls).

Sometimes, the schedule specifications will include specific requirements for the inspection, testing and commissioning processes. Usually, the specification requirements are more general. Regardless, it is in the best interest of the project to include activities for these quality assurance activities in the schedule.

Not having a series of activities for the development, submittal, review, and approval of a fire alarm test plan or mechanical system commissioning plan creates a large risk for the schedule. While everyone may understand these plans are necessary and the testing is required before substantial completion can be obtained, many project teams don’t include the entire process in the project schedule. We also need the actual start-up and pre-operational inspection and testing work, the commissioning of the system, and the performance testing in the schedule. Depending on the size of the project and system, these may or may not occur at the same time. For a smaller renovation project, it’s not unreasonable to expect the inspection, testing and commissioning of a system will all happen at the same time over the course of a couple of days. On a larger more complex project, there may be a third-party commissioning agent and the system may be large and complex enough that the inspection and pre-operational testing will take several days with additional coordination with other systems.

Not including activities for this work will create a delay situation at the back end of the project, when you can least afford it.

We need to put a lot of effort into looking at the end of project QA and closeout work to make sure we include everything we need. If we do not have the time for this work allocated at the beginning of the project, we will certainly not have any room to execute this work at the end of the project.

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. CPM Schedules for Government Construction Projects.

You’ve been successful in winning a government construction contract. Maybe it’s a project administered by a Federal agency like the United States Army Corps of Engineers or the Veteran’s Administration. Maybe it is a state agency. At any rate, if you haven’t started developing the project’s Baseline Schedule, now is the time to start.

The place to start is the CPM schedule requirements from the RFP docs. Although they may be found in different sections, almost every agency has CPM schedule requirements in their contracts. They all vary, but they are usually much more stringent than the commercial CPM schedule requirements most contractors are comfortable with.

Are you prepared to develop your baseline schedule while meeting these more stringent requirements?

There are usually limitations on the duration for work activities. There can be requirements for activity coding which you may not be familiar with. You need to understand how to develop project-level calendars, resources and activity code.

A CPM Schedule Consultant with experience developing and managing these types of schedules is a valuable resource for you. Even if you plan to keep your schedule work in-house, having an experienced CPM schedule consultant available for advice and mentoring is a good bet.

There is nothing magical or overly difficult about meeting the CPM schedule requirements, but it can be costly in terms of time and aggravation if you have to keep correcting the baseline schedule when you’re unable to get owner approval. You will have your hands full getting the site safety plan or accident prevention plan accepted. There is also the Quality Control Plan. These administrative submittals and other early submittals and subcontractor buy-out will keep your PM team tied up for the beginning of the project. A little help with your schedule development will relieve the pressure of getting all the required preconstruction work completed so you can start mobilization and doing the real project work.

And most importantly, you must have your baseline schedule accepted to be able to develop your first progress update and submit your invoice.

The key is paying attention to all the detailed requirements. These agencies usually enforce conformance with these specifications. The development of calendars, the special activity code structure, the method of assigning resources and cost, and the use of constraints are all spelled out in great detail.

Don’t be afraid to reach out for help. There are many CPM schedule consultants with plenty of experience working with these CPM schedule requirements. Find someone you’re comfortable with and let them take some of the burden from you….

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. Developing the Project Schedule Plan.

When you’re bidding a project, do you start developing a schedule plan? Or plan your schedule?

Before we ever start developing activities, we should plan the project, and this includes planning the schedule.

We need to determine how we plan to sequence the major portions of the work, establish required and preferential phases, break the project down into smaller deliverables based on area, CSI code, sub-contractor, type of activities – contract milestones, procurement, administrative activities…

This information is probably part of the cost proposal development process and provides us with the building blocks for developing the WBS.

We also need to have an idea of what type of activity calendars and coding we will need to use. The resources we will need to develop can be based on the subcontractor or CSI deliverable list.

As a CPM Schedule Consultant, I use this information to develop a schedule plan. I use this plan to develop the project WBS, activity coding, resources, and project calendars. I develop these before I ever start creating the activities for the schedule. Having the WBS developed helps ensure we have the entire scope of work in the schedule. Having the activity coding developed allows me to assign these items to the activities as I create the activities. This helps with filtering and sorting to assign hard and preferential logic and for reviewing work for specific resources or subcontractors for trade stacking and for reviewing specific areas for trade congestion. It’s just easier to assign the Responsibility and CSI activity coding along with assigning the resources. This saves time and avoids mistakes. Having the calendars developed helps with setting the original durations once we have all the logic assigned.

Planning the project as well as the schedule is the important first step in developing the project 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. Too much Detail.

When we develop the Baseline CPM Schedule for a construction project, we need to develop the WBS to establish the project deliverables.

To what level of detail is this required?

The general idea is to decompose the project deliverable down to the Work Package level. For construction, this could be taking the WBS down to an area of structural foundation for a large project. It is really taking the deliverable down to the point that it can be easily identified and measured.

We then develop the “work” activities that need to happen to produce this deliverable.

Basically, we develop the list of activities, sequence them, assign the resource(s) and determine the Activity Duration, and assign the activity’s Budgeted Cost. There are also the Activity Code, Calendar, and Role assignments…

Many specifications have limits on the number of Work or Calendar Day duration a “work” activity may be assigned. A good rule of thumb is “not to exceed the reporting period”. I like to cap my “work” activities at 20 Work Days or less. An activity should only have one responsible party performing the work. If an activity only has one party performing the work and the duration of the work is going to exceed 20 Work Days, perhaps it is best to break the work area down to allow smaller durations. It is difficult to accurately measure the performance of activities with large areas or durations.

The use of activities with large Activity Durations also leads to the use of Start-to-Start and/or Finish-to-Finish relationships to model the work which is now running concurrently with other large duration activities. This should be limited. The overuse of Start-to-Start and/or Finish-to Finish relationships is a basic problem for many detailed project schedules. Makes a pretty Gantt Chart, but does not allow adequate control and measurement of scheduled work.

Most deliverables should have activities with durations much less than 20 Work Days. They should not all be 1 Work Day unless that is actually what it takes to model the work of several parties. Usually, the “work” could be broken down to 5 days to excavate the foundation, 2 days to install reinforcing steel and any vapor barrier or blockouts, and 1 day to place concrete and an activity with a period of time for concrete curing. Breaking the work down to this level allows the work to be easily measured and managed. Too often I see a “Place Foundation Concrete” activity with a duration of 10 Work Days. No cure activity. No idea if cure time is included or not…. No idea when the excavation should complete or when the reinforcement placement starts…. Most likely, the formwork and reinforcement work will run concurrently at some point and the concrete placement will be driven by the finish of the reinforcement work and inspection. If there is a delay in delivery of reinforcement steel, we should be able to accurately model that…..

The idea is to develop a schedule which is manageable and has enough detail to control the work. Pretty simple.

If there is more than one contractor performing the work, you probably need to break down the work further. If a series of activities are all running concurrently, perhaps it would be best to break the work down into smaller areas. The goal is to use Start-to-Start and/or Finish-to-Finish relationships as little as possible. Using Finish-to-Start relationships is almost always the best way to model the work. This usually requires breaking the work down into smaller pieces…

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. Contract Duration and the Finish Date.

When we develop the Baseline CPM Schedule for a construction project, we need to know the contractual dates for Beneficial Occupancy, Final Contract Completion, and any other contractually required dates for deliverables.

The calendar day difference between NTP and the Required Contract Completion Date determines the project duration in Calendar Days.

Various organizations use various names for these required dates. There is NTP for Notice to Proceed. This can be for design, construction of any segment of the project. In construction, it is usually for the start of construction, but Design-Build projects typically have NTP for Design and even interim NTP dates. The names for Contract Completion vary greatly. Beneficial Occupancy; Start Operations; Contract Completion Date; BCOM…. The list is long.

Whatever the terminology, we have to end up with a project schedule that fits into this period of performance.

We develop the schedule based on input from all stakeholders. We verify we have included the entire scope of the project. We make sure we sequence the work in a constructible manner. We use accurate durations for work activities.

Does the Project Schedule then report a finish date which meets the contractual requirement?

More often than not, it does not. Correcting this is another issue.

So, what drives the contractual finish date? Is it a business decision based on a valid business need? Is it an organizational need for a change in operations? Is a specific date to meet some public good?

Many times, the contract completion date has been established based on someone’s best guess to create the period of performance. Sometimes, the Capital Projects Team decided on the period of performance based on another similar project. Sometimes funding issues drive the period of performance.

Whatever the reason, the project must be completed within the period of performance or some type of punitive action will result. This is just one more reason to develop a robust and dynamic CPM schedule with which the Project Team can manage work proactively. The effort expended to create and manage a quality CPM schedule is easily recovered with the savings gained through improved management of work and adherence to the required finish date. Whatever it is called…..

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 Codes and Organization.

When the schedule is developed, how do we determine the Activity Coding for each activity?

What is an Activity Coding Structure?

Many PM’s don’t know or care about the Activity Coding. Unfortunately, they are missing out on the use of a great tool.

I’d like to offer several reasons for spending the time and energy to develop and use Activity Coding.

Activity Codes are developed for the schedule based on specification requirements and a Schedule Management Plan. It can be as simple as a specific assignment for phasing. More often an Activity Code Structure is developed to include specific phasing of the project, responsibility for work, areas of work, CSI assignment, weather sensitive or not, and type of work.

I like to develop the schedule Activity Code Structure prior to building the activities out. I usually do it when I set up the calendars, resources, and WBS. After all, it is based on the plan for organizing the schedule and reporting for the various stakeholders. It is also used for schedule analysis.

Once the Activity Code Structure is set up, (Along with the calendars and calendars, resources, and WBS) we can start building out the activities for the project schedule.

If you develop the string of activities for a specific trade, which is how I usually start out the development of each trades’ work, it is easy to assign the resource and activity coding as you assign the activity calendar and resource. By having already established the Activity Code Structure, there is already a ready list of choices. This prevents inadvertently assigning similar coding for the same item.

So, we develop all the activities by WBS with the appropriate activity calendar, resource and Activity Coding.

Now we can sort and group in a multitude of ways based on the Activity Coding Structure we planned and executed.

We can group by responsibility and sort by Start Date if we have already assigned the logic. Or we can sort by Activity ID if we added the activities sequentially in the order of execution. This makes it easier to manage adding the logic. We can then group by area to see how we need to coordinate the work between trades. This is very handy for establishing preferential logic.

We most often use the Activity Coding for Layouts and presentations.

Grouping the schedule by phase and then area is a popular layout.

We can also filter by responsibility which allows us to analyze the planned sequence for each trade and verify scope. If the logic is complete and there are many activities planned for the same work period, resource allocation may be an issue. This layout allows us to assign preferential logic to assign resource flow.

There are many reasons for developing a robust Activity Coding Structure. We use them often and they offer a great method of organizing the activities for analysis.

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. 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. Use of Relationship Lags.

When your contractor develops the project baseline schedule, do they use many relationship lags? Do you know?

A relationship lag is an imposed period of time between the predecessor and successor activity. A common use in a Start-to-Start (SS) relationship with a 2-day lag. Perhaps the contractor’s plan is to start finishing drywall 2 days after the drywall installation begins. This allows the work to run concurrently.

There absolutely are times when work can and should be modeled this way. However, care should be taken to ensure an open start isn’t inadvertently created. (This is a future topic)

The problem arises when the series of work activities is developed with SS relationships with an assigned lag. This may indicate the work is not developed to enough detail to allow Finish-to-Start (FS) relationships to drive the work. The issue is, once the start of the predecessor is actualized, the start of the successor is only dependent on the calendar set for use for lags. This may not match the number of days intended. If this work happens to fall on the Longest Path, this path is now driven by a calendar. I prefer to limit the use of SS relationships in general, much less with assigned an assigned lag.

Then there are the Finish-to-Finish (FF) relationships with lags. These allow the successor work to finish only after the predecessor’s finish date plus the lag duration. 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 with the lag. This creates an issue in itself. (This is a future topic)

The most serious issue is when the relationship is an FS with a lag. What does the lag model? Should there be an activity to establish this difference in the relationship finish to start? Most likely, the answer is yes. There is nothing wrong in using an FS with a lag to have the lag represent say, cure concrete. I personally prefer to add the cure concrete activity with the number of days required. This is more transparent. The lag is not visible and creates a non-work period seen in the Gantt Chart bars and can cause confusion.

Then there is the negative lag, or leads. Many schedulers like negative lags and use them as a viable way to model the plan. When I see an FS relationship with a negative lag, I wonder why the use of a SS relationship with a positive lag could not have been used. The use of the negative lag may better represent the thought that the successor cannot start until 3 days prior to the finish of the predecessor. And this 3 days is the critical period. I personally prefer to model this type of plan with a SS with a lag or to further break down the activities to allow the use of FS relationships to model the work.

Finally, there are the SS relationships with an assigned lag that is larger than the activity duration forcing the model to show the work as an FS relationship. Why not just use the FS relationship? Unless there is a reason to model the work this way, it just doesn’t make sense to do so.

The relationship lag, if used correctly, can allow the schedule to model the plan. It is my opinion that the use of lags should be kept to the absolute minimum and only used to model SS or FF relationships.

But remember, the lag follows the calendar set for use for lag calculation. If the predecessor calendar is set for use, and the predecessor is assigned to a 5-day work week calendar, the lag will follow that calendar and the duration will be in work days. So, a 3-day lag could become a 5-day delay between the relationships if the lag spans a weekend. This may not have been the case when project work was planned and the schedule was developed and the lag did not span a weekend. Remember, this is not transparent, only someone who understands the schedule software and has access to the native file format can verify this. Unless the schedule layout includes the columns which show relationships with lags and the column that shows calendars. Even then, you need to know what the actual non-work days for the specific calendar are.

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