Scheduling

Integrating Subcontractor Data into an Integrated Master Schedule

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Generating and maintaining a project’s Integrated Master Schedule (IMS) that meets management needs as well as customer requirements is difficult under the best of circumstances. The challenge becomes even more complex when subcontractor work effort must be incorporated. Issuing a subcontract is, in effect, handing off a portion of the work scope to an outside entity that becomes responsible for performing that work and meeting all technical requirements. 

Another consideration for contractors where Earned Value Management System (EVMS) contractual requirements apply is whether the subcontractor is considered a major subcontractor because of the contract value, scope of work, or high risk factors. The EVMS requirements are flowed down to these major subcontractors; they will have the same contractual requirements and challenges as the prime contractor. Most subcontracts do not fall into this category. Many are small, short term, or firm fixed price (FFP) subcontracts. 

Regardless of the category of the subcontractor, the subcontractors and the prime contractor all need an IMS to plan and coordinate work effort as well to measure progress. Using FFP subcontracts on development projects has the potential to increase risk significantly when expectations for scheduling rigor are not clearly defined. 

A Real World Example

H&A EVM consultants supported a multi-billion dollar development project that illustrates the challenges with integrating subcontractor schedules into a prime’s IMS. The prime contractor had two major subcontractors with EVMS flow down requirements. They also had 22 FFP subcontracts without EVMS flow down requirements. 

These FFP subcontracts were also mission-critical. The prime’s first priority was to define the required schedule format and data content in the request for proposal (RFP) to the subcontractors. Standardization was essential, along with specific instructions to ensure the schedule data could easily be incorporated in the prime’s IMS. 

As the basis for a customized project specification, the team selected the Integrated Master Schedule (IMS) Data Item Description (DID) DI-MGMT-81650, an earlier DID that preceded the Integrated Program Management Report (IPMR) and Integrated Program Management Data and Analysis Report (IPMDAR) DIDs. The requirements were simplified and trimmed to selected sections in the DID for the detailed schedules. The document was assigned a specification number within the prime’s document management system so it could be used for future procurements. 

Early Schedule Submittals: A Wake-Up Call

All the subcontractors dutifully proposed and were awarded subcontracts. The FFP subcontractors were required to submit initial schedules using the scheduling tool of their choice at the end of the first month of performance. To ensure compliance, the prime contractor tied the subcontractor’s first payment milestone to the acceptance (receipt, review, and approval) of their first schedule. 

This turned out to be one of the best decisions made during project startup. 

Those first schedules quickly revealed that many of the lower tier subcontractors had no experience developing logic-driven schedules that could comply with the reduced requirements document. They were unable to generate even the most basic project schedule. It was an eye opener to realize that while the first tier companies and most of the second tier companies did know about project scheduling, some of the second tier and all of the lower tier companies lacked that expertise.

The Solution: A Prime-Led Schedule Development Workshop

The prime’s schedule team, largely comprised of H&A schedulers, quickly initiated a week long on-site workshop open to all subcontractors who wanted help building their IMS. Every one of them signed up as they recognized acceptance of their schedule was a prerequisite for payment. 

Prime contractor personnel were assigned to each subcontractor to help them build schedules that met the requirements. Most of the subcontractors were able to produce an acceptable schedule within the first three days. The other subcontractors required the full week.

The workshop approach provided two major benefits.

  1. The subcontractors gained experience in developing a logic-driven schedule that they could maintain and status. They had a better understanding of what the prime contractor expected them to provide. 

  2. The prime’s schedule team gained a better understanding of each subcontractor’s scope of work and execution strategy. They had a better picture of the entire IMS as well as interdependencies. Without this knowledge, the next step of determining the best strategy to incorporate the subcontractor’s schedule data into the prime’s IMS would have failed. 

Strategies for Incorporating Subcontractor Data into the Prime’s IMS

The NDIA Integrated Program Management Division (IPMD) Planning and Scheduling Excellence Guide (PASEG) is a useful source of information on scheduling best practices. The section on External Schedule Integration offers basic guidance on flowing down detailed scheduling requirements to subcontractors. It also provides a short list of things to consider, such as coordinating dates and change control:

“Status dates should be consistent between the prime contractor and supplier schedules. If the subcontractor’s schedule update is to a different point in time, it could potentially affect the IMS analysis results. If it is not possible to have consistent status dates between the various schedule elements then implement a strict process, with support of all parties, to manage the impacts.

Change control procedures are established and understood. The prime contractor should clearly communicate which type of schedule changes will require pre-approval before incorporation and which type will require coordination only or documentation upon submittal. The lack of a disciplined change control process can result in disconnects between the prime contractor and subcontractor’s schedule.”

Remember the prime contractor’s IMS includes a baseline and a current schedule. The complications can be significant when all the variables are considered such as calendars, mix of schedule tools and options, scheduling techniques, resource loading, and custom fields.

That still leaves the question of how to incorporate the schedule data from an external source into the prime’s IMS. The PASEG outlines three approaches.

  1. Full integration where the entire subcontract schedule is incorporated into the prime’s IMS. 

    Pros: Provides maximum visibility into the critical and driving paths as well as forecast completion dates.

    Cons: Often not feasible with a large number of subcontractors. Mix of scheduling tools complicates the process. 

    Use Notes: This option is often reserved for major subcontractors or teaming partners. Works best when the prime and subcontractor are using a common scheduling tool or the subcontractor has direct access to the prime’s IMS scheduling tool to maintain their data. Otherwise, the prime must incorporate additional processes to import the external data into their IMS. There are other complications, as different schedule tools calculate dates differently, that will need to be handled in the integration process. 

  2. Using interface milestones. 

    Pros: Easier to implement and maintain. Yields the best results with less complex or lower risk subcontractors. 

    Cons: Provides less insight into the subcontractor’s current schedule performance. It does not easily support critical path analysis when paths run through subcontract work effort.

    Use Notes: Requires the manual update of each interface milestone to reflect the latest forecasted dates from the subcontractor’s schedule. The prime must ensure their IMS is properly coded. Contractors often use “External Inbound” and External Outbound” codes along with a subcontractor code and any other codes needed to identify who is receiving/giving to whom.

  3. Representative model. This is a middle ground approach between integrating the entire subcontractor’s schedule into the prime’s IMS and using interface milestones. Requires a summarization or representation of the subcontractor’s work to be entered into the prime’s IMS.

    Pros: Provides a summarized version of the subcontractor work effort that retains enough schedule logic for critical and driving path analysis. 

    Cons: IMS content must be carefully entered and maintained to retain the required relationships to the external schedules for accurate critical path analysis. Requires a higher level of schedule discipline and a defined process to ensure the accuracy of the data between the external schedules and the prime’s IMS. 

    Use Notes: It is often beneficial to provide the subcontractor with a copy of their schedule that includes an extra column that identifies the prime’s task ID that is the “parent” of the summarized or consolidated work. In the initial IMS submission from the subcontractor, the prime added a custom field (Prime Parent ID). That IMS file was returned to the subcontractor, and the use of the special field was agreed upon. In each subsequent submission by the subcontractor, the prime team checked for tasks with no “Prime Parent ID” and added one that would allow integration. This kept the two companies’ schedules synchronized. If changes were made by the prime team that changed the field data in the subcontractor’s IMS, the changes were coordinated. A recommended practice is to group and sort the subcontractor schedule by the prime’s IDs to ensure that it is done properly. 

What Worked for the Complex Development Project

In the situation described earlier, the schedule team determined a hybrid approach was the best solution, depending upon the subcontractor’s scope of work.

  • The full integration approach was quickly eliminated; it was impractical. There were too many schedules, and some were too complex. It would have been a logistical nightmare. 
  • Selected simple FFP subcontract work effort was incorporated using the milestone method. The schedule milestones were carefully aligned to the payment plan milestones so that one set of milestones served both purposes.
  • For the subcontracts with EVMS flow down requirements and the other subcontracts, including some FFP subcontracts, the representative model was used. The prime’s control account manager (CAM), responsible for the subcontractor’s scope of work, was required to condense the subcontract schedule into a representative model that made sense to the CAM. The most common ratio turned out to the 10:1, with 10 subcontractor tasks rolling up to 1 prime contractor IMS task, carefully maintaining the prime’s control account and work package structure. With proper coding, the subcontractor schedule could be easily reviewed and analyzed by the CAM as well as other project personnel.

Need help establishing strategies to integrate subcontractor schedule data?

Every project presents unique scheduling challenges, and the approach for integrating subcontractor data often needs to be tailored to fit the situation. H&A earned value consultants and master schedulers have seen and solved them all. With deep experience across diverse industries and project types, our experts deliver the insight and leadership needed to help contractors implement practical, results-driven solutions for integrating subcontractor data. Call us today to get started.  

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Understanding the As Late As Possible (ALAP) Scheduling Option in Practical Terms

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Understanding the As Late As Possible Scheduling Option in Practical Terms

Many project professionals have spent entire careers without ever using the As Late As Possible (ALAP) scheduling option, although the underlying idea feels familiar. Why? Because it’s very similar to the “just-in-time” concept widely used in manufacturing and logistics.

In materials management, just-in-time means having what you need arrive exactly when you need it, minimizing storage costs and reducing inventory. The same principle can apply to project labor, but with some important cautions.

The “Right Time” for Project Work

On development or design projects, doing work too early can be counterproductive. If designs change, early work may become obsolete, forcing costly rework. The “right time” to perform a task is often determined by schedule logic. In some cases, however, it can also be guided by the ALAP constraint.

Before we explore when ALAP makes sense, let’s quickly review the two primary constraint options in Microsoft Project (and most other scheduling tools).

ASAP – As Soon As Possible

As soon as possible:

  • Is the default setting for forward-scheduled projects (when you set a project start date).
  • Means tasks are pushed as early as possible, immediately after their predecessors finish.
  • Is ideal when you want the earliest possible completion and clear visibility into float/slack.

In an ASAP chain, every task begins at the earliest opportunity, pushing resources as far to the left as possible on the Gantt chart as illustrated in Figure 1.

Figure 1: As Soon As Possible Scheduling Option
Figure 1: As Soon As Possible Scheduling Option

ALAP – As Late As Possible

As late as possible:

  • Means tasks are scheduled as late as possible without delaying the successor or project finish date.
  • Is used in backward-scheduled projects (those planned from a fixed finish date) or when you want to defer work until the last responsible moment.
  • Microsoft Project automatically places each task at the latest feasible start date that still satisfies all constraints.

Switching a chain of tasks to 100% ALAP dramatically shifts all work to the right on the timeline as illustrated in Figure 2. The impact on management is significant: Every task now has zero total slack, which means any delay, even one day, directly delays the project finish. Multiple paths can appear “critical,” making control and reporting more complex.

Figure 2: As Late As Possible Scheduling Option
Figure 2: As Late As Possible Scheduling Option

When ALAP Makes Sense

There are legitimate reasons to use ALAP selectively. For example:

  • When a task consumes resources you don’t want engaged early (e.g., expensive equipment rental or specialized consultants).
  • For just-in-time deliveries or procurements where early completion has no benefit.
  • When modeling backward scheduling. For instance, working from a fixed delivery date toward today.
  • A mixed schedule. Mostly ASAP but with a few ALAP tasks can balance flexibility, cost control, and realism as illustrated in Figure 3.
Figure 3: A Schedule Using ALAP and ASAP
Figure 3: A Schedule Using ALAP and ASAP

A Real-World Example

One of H&A’s senior scheduling consultants once faced this exact dilemma while helping to prepare a multi-year, multi-billion-dollar defense proposal for a project with strict annual funding limits. 

With less than two weeks before the submission deadline, the Proposal Director was exasperated: “I keep asking the engineers what can be delayed! Why does everything have to happen up front? The front-loaded schedule is blowing our funding cap!”

A quick inspection revealed the problem: every task was set to ASAP. The entire effort was jammed toward the beginning of the timeline, creating a massive early demand for resources. After several failed attempts to persuade the engineers to move work later, the consultant proposed something unconventional: “Let’s flip the question. Instead of asking what can we delay, let’s ask what must be done now.”

The H&A scheduling consultant converted the entire schedule to ALAP, instantly shifting all work to the far right of the timeline. The resulting view inverted the problem, from overspending early to under-spending, and gave the team a new way to discuss priorities.

In meetings, engineers were asked to move tasks from ALAP to ASAP one at a time, stopping when the annual funding limit was reached. The discussion changed from “Why can’t we do this now?” to “What can we afford to do this year?”

The result wasn’t elegant, but it solved the immediate problem: the funding limits were clearly observed, the resource profile became manageable, and the trade-offs were visible to everyone.

How ALAP Affects Critical Path and Risk

Because ALAP tasks consume all available float, they appear critical even when they may not truly drive the project finish. This can obscure the actual critical path, making it difficult for project managers to distinguish between genuine schedule risks and artificial ones. In Earned Value Management (EVM) environments, this matters. Earned value metrics depend on knowing which tasks drive completion. Excessive use of ALAP can lead to misleading forecasts and distort DCMA data quality metrics such as the Total Float test and the Critical Path test. For this reason, auditors often recommend using ALAP sparingly and documenting the rationale wherever it’s applied. 

Note: in a sophisticated scheduling environment, it is possible to make a copy of the integrated master schedule (IMS) and revert to ASAP to look for critical paths in the normal sense.  

Combining ALAP with Other Constraints

In practice, project managers often use a blend of constraint types. For example, you can combine ALAP with “Must Finish On” or “Start No Earlier Than” dates to simulate external dependencies such as contract milestones, funding release dates, or material delivery windows. This hybrid approach allows the schedule to model reality while maintaining logical control. However, it’s important to track these constraints carefully. Too many “hard” constraints of any type can reduce the schedule’s dynamic nature and make automated forecasting less accurate.

Guidance from Industry and Agencies

Industry and government scheduling guides consistently advise restraint when using ALAP. The DCMA data quality tests consider the presence of ALAP tasks as a potential red flag because they can mask schedule float and obscure the true drivers of program completion. Similarly, the GAO’s Schedule Assessment Guide recommends minimizing artificial constraints and using logic-driven sequencing whenever possible. ALAP may be appropriate for modeling constrained resources or fixed delivery milestones, but it should always be justified and documented. Within DoD and NASA programs, reviewers often require clear evidence that ALAP usage is intentional, controlled, and limited to well-understood modeling cases. It should never be used as a workaround for poor sequencing.

Key Takeaways

  • ASAP emphasizes early starts, clear float visibility, and traditional forward scheduling.
  • ALAP emphasizes delayed starts, tighter resource control, and is useful in backward or funding-constrained planning.
  • Use ALAP sparingly and intentionally as it can obscure float and create multiple critical paths.
  • In creative problem-solving, toggling between ASAP and ALAP can reveal insights about timing, funding, and necessity that might otherwise remain hidden.

Final Thoughts

The ALAP constraint is a powerful but double-edged tool. It can simplify discussions about funding limits, resource phasing, and timing priorities, but it also carries risk if used indiscriminately. Like most features in commercial off the shelf (COTS) scheduling tools, its value depends on the user’s intent and discipline. The best project schedules blend logic, transparency, and flexibility. Understanding when to use ALAP (and when not to) can make the difference between a reactive plan and a truly managed one.

Interested in Learning How to Use More Advanced Scheduling Techniques?

Master schedulers skilled at asking the right questions to solve project management challenges hone their craft based on years of experience and working with other scheduling experts. There are always opportunities to learn more. H&A routinely offers basic, advanced, and tailored scheduling workshops taught by senior master schedulers with decades of experience in all types of project environments using common scheduling tools such as Microsoft Project and Oracle Primavera P6. Give us a call today to get started. 

Humphreys and Associates also offers basic and advanced EVMS training as well as tailored EVMS training that aligns with a client’s EVM System Description. 

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