9/18/23, 11:48 AM
Successful Design Scheduling - Source
Bonus Technical Article / October 5, 2021
Successful Design Scheduling
Christopher W. Carson, CEP DRMP PSP FAACE;
Aaron Fletcher, PSP; Noah A. Jones, PSP;
and Leo Carson-Penalosa
Abstract–Delays often originate within the architectural and engineering (A/E) design
effort. The schedules developed to plan, organize, and monitor design tend to be high-level
and not very effective to accurately model the work at a level of detail that allows for on
time, on budget, and quality completion. When the schedule does not provide the right level
of detail or complexity, its value for monitoring is limited. Sometimes there is even a failure
to recognize the difference between consumed hours and progress. Failure to use the right
schedule can lead to performance issues resulting in late design delivery, over budget
delivery, or poor-quality design delivery, or any combination thereof. A well-designed and
managed A/E design schedule promotes quick and accurate updates, supports proactive
https://source.aacei.org/2021/10/05/successful-design-scheduling/
1/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
analysis to minimize delays and claims, and aligns with other project controls functions to
enable integrated cost-schedule-risk design scheduling. The authors, working for firms that
provide engineering design services, have experience in working with the designers to
develop the right level of detail for the design portion of a project, to establish a stage-gate
approach to design milestones so they can align with cost, schedule, and risk monitoring,
and so performance can be accurately measured. The authors bring a wide range of
perspectives, from process engineering design scheduling to design-build A/E scheduling,
to construction manager (CM) agency A/E monitoring, to CM at risk A/E support scheduling.
This article will offer a proven approach that demonstrates guidelines for schedule design,
development, monitoring, analysis, updating, and reporting, as well as set the benchmark
to facilitate mitigation when necessary. This article was first presented as PS.3427 at the
2020 AACE International Conference & Expo.
Introduction
Design scheduling is handled by several different parties, or parties working in several
different roles and contracts. A/Es might work directly for the stakeholder or employer on a
project, a contractor in the form of a design-builder, or a contractor working as a
concessionaire for a public-private-partnership (PPP or P3).
Background
To discuss this issue, it is important to define design scheduling and establish the value of
providing professional critical path method (CPM) scheduling to plan and manage the
design process. Many projects fall behind during the design process, in design-bid-build
(DBB), design-build (DB), engineering-procurement-construction (EPC), and construction
manager at risk (CMAR). Each of these project delivery processes has its own challenges,
but design schedule management is a primary one. The complexity of architecturalengineering (A/E) design is mostly because of the variety of disciplines necessary to
complete a project, the scope development maturity, and the ability to assess progress in
design. At a given stage of design, say 30% design development, the structural design
might be at 60% complete, while commissioning might be at 0% complete. Developing a
schedule of this sort can be difficult and monitoring can be even more difficult.
What is Design Scheduling?
Design scheduling is the act of planning the design activities, developing a CPM schedule
for those design activities, and maintaining that schedule through a regular updating
process that captures progress information, assesses performance, predicts trending and
https://source.aacei.org/2021/10/05/successful-design-scheduling/
2/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
delay issues, and provides corrective actions to enable the design to complete all
milestones on time.
How is it Commonly Handled?
Typically, A/Es develop and maintain their own progress schedules using different software
and methods. Since the schedules are most often not shared with other stakeholders, there
is a reduced need for a high level of technical scheduling effort as would more often be
seen in the construction process. However, all designs evolve through phases, a series of
increasing levels of scope definition, and assign milestones representing the completion
percentage at the end of each phase. In many projects, especially the more successful, the
milestones act as the gates at which cost and schedule reviews are performed to ensure
that the design is progressing and maintaining the original budget and duration established
in the conceptual stage. As cost and schedule are verified at each stage, the gate opens
and allows design to move into the next phase.
This is often called a stage-gate approach, and studies have shown that when done
appropriately, the project is more likely to achieve the design-to-budget goal, defined as
ensuring that the design stays within the planned budget as it evolves to full maturity.
Meeting this goal is enabled by a formalized process of detailed review at the different
levels of scope definition, ensuring that the budget, schedule, and risk issues have been
updated and validated. Combined with a good contingency process, this evolving process
of projects controls support and verification, helps identify any design issues that are at risk
of driving up budgets and extending schedules.
Value of Design Scheduling
Depending on contract type, many projects cannot proceed into procurement and then
construction without design progressing as planned. Many projects under DB and EPC
delivery methods progress to procurement and or construction without a completed design.
EPC or DB project durations tend to be both quite long duration and technically complex
projects that often require multiple phases of design. For these projects, the design effort is
often scheduled in the CPM schedule. In both cases, design costs are related directly and
only to labor, so productivity and production are both important. Issues in design delivery
are caused by taking more time than anticipated or quality concerns. Using the stage-gate
approach limits both potential sources of over run.
Risks of a Weak Design Schedule
https://source.aacei.org/2021/10/05/successful-design-scheduling/
3/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
If the A/E does not have a plan for completion of the design within the planned duration, it is
unlikely that they will engage the right individuals, or the number of individuals needed, and
the design effort will fall behind, ultimately delaying the start of the project.
There are also risks associated with the designers working without project controls
monitoring, so the scope of work can grow, or features can be added, since there is no
feedback related to the costs of the design, or the feedback comes after the design is
complete. This is called scope creep when additional scope is added, often unintentionally,
or gold-plating, when the A/E designs more expensive features than originally budgeted,
which will increase the costs and duration often unbeknownst to the stakeholders.
Benefits of a Good Design Schedule
A well-designed and managed design schedule will allow the project to meet the
stakeholders’ goals in progressing through the project phases into procurement and then
construction as scheduled and within budget. Conceptual project schedules will show time
allowed for phases of design, producing increasing levels of scope definition or design
maturity, until final construction documents are produced.
As design progresses, according to the original schedule, staff work is assigned consistent
with the design budget. Senior, more expensive, designers are assigned for the innovative
and technical requirements. More junior, less expensive, computer design operators
produce the details and production drawings. Each stage-gate milestone receives reviews
to ensure compliance with budget, schedule, constructability, value planning, and risk.
When done properly, the design matures in a controllable fashion, the stakeholders are
aware of the adherence to the goals, and the phase-gate process allows corrective actions
when there are deviations from the original benchmarks.
Studies Related to Design Scheduling
The value of this effort is reinforced in a 2014 study, by McGraw Hill, which notes that, “The
ability to develop a set of documents that meet the stakeholder’s program requirements
and are constructible within budget is unanimously cited as the most-valued metric for
design team performance . . .” [page 6, of reference 8]
In the same study, the second highest cause of uncertainty with greatest impact on cost is
stakeholder program or design changes and the third and fourth are design errors and
design omissions, with the program design changes ranking significantly greater than the
design errors/omissions. [page 14, of reference 8] Progressing through the design process
with a weak phase-gate process can allow design development that is focused only on the
https://source.aacei.org/2021/10/05/successful-design-scheduling/
4/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
design and not the budget or schedule, making it subject to scope creep. Many design
changes can cause delays to other disciplines and hours expended on designing features
or even options that may or may not be adopted. Without a phase-gate approach delays to
time and budget, due to accumulated changes, can and do go underestimated until the end
of the design process causing overruns in budget and/or time. The impact on the schedule
can be surprisingly significant since budget overruns that are discovered late in the design
process will often create a need for cost reductions. These cost reductions, commonly
poorly named as value engineering efforts, can become increasingly critical as the team is
trying to get construction work started. Value engineering should take place much earlier in
the design process, in fact, it can be done as soon as there are drawings to review and the
next step after value planning. However, when the budget is overrun and there is pressure
to release construction drawings to start work, what is called value engineering is usually
just quality reductions, materials changes, or even scope deletion. A detailed state-gate
project controls effort integrated with the design process can help ensure the project is
designed to the original budget, or if there are legitimate changes that require budget
increases, the stakeholder is notified early enough to minimize impact on the schedule.
Project Delivery Methods Associated with Phases of Design
The type of project delivery method contributes to some of the uncertainties in A/E design
since in traditional delivery the A/E has ultimate quality control that is tested by the bid
market. In many other delivery methods, the contractor either takes over the design or is
intimately involved in monitoring design as it advances through the stages from conceptual
to bid or tender documents.
Design-Bid-Build – Complete Design = Stakeholder to 100%
The traditional, private sector project delivery method typically involves three sequential
project phases: The design phase, which requires the services of a designer who will be
the designer of record for the project; the bid phase, when a contractor is selected; and a
build or construction phase, when the project is built by the selected (typically low bid)
contractor. This sequence usually leads to a fixed-price contract. [page 3, paragraph 2 of
reference 7] In a design-bid-build type delivery method, the stakeholder will be responsible
for most if not all aspects of the design.
A risk to a stakeholder with a design-bid-build delivery method is that they warrant the
sufficiency of the plans and specifications to which the selected contractor will ultimately
build the project. This means the stakeholder/designer will be responsible for any issues
that may arise during construction related to errors or omissions in the plans. There is little
or no opportunity for the designer and contractor to collaborate during the design phase,
https://source.aacei.org/2021/10/05/successful-design-scheduling/
5/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
which can ultimately contribute to time and cost overruns due to undiscovered design
errors. Further, without input from experienced construction expert staff, the design will
likely be less constructible and efficient.
These design errors or omissions can often stem from lack of planning during the design. A
well-developed stage-gate approach with clearly defined design deliverables helps the
teamwork towards distinct achievable interim goals as opposed to three or four major
deliverable dates. Also, early involvement of the contractor or construction manager can
help to recognize many of these potential issues from a construction point of view. For this
reason, part of the stage-gate approach should include constructability review.
Constructability reviews are part of the evolution from value planning in pre-design to value
engineering and constructability reviews during design as drawings are produced. These
quick reviews by construction experienced individuals ensures that designs can be built as
they bring eyes of physical, real-world constraints to the design. Questions generated
during this process always add value and support a more robust design.
EPC – Stakeholder to ~15%, Contractor to 100%
In the engineering, procurement, and construction (EPC) type of project delivery method
used commonly in industrial and process industries, the stakeholder performs studies or
research, decides to go forward with a project, determines the results needed from the
project, develops the appropriate scope definition to ensure understanding of the
stakeholder’s needs, then hands the scope definition over to the selected contractor who
proceeds with advancing the conceptual phase design, moving on to feasibility, to front-end
engineering and design (FEED), to detail design, then finally to implementation.
Generally, these are lump sum/fixed price contracts. This places the risk of final scope
definition and performance on the contractor. In addition, it makes it easier for the
stakeholder since managing one contractor is simpler than managing several contractors,
and much simpler than interceding in the historical conflicts between contractors and
designers. Using an EPC firm will allow for clean lines of communication from the design to
construction phases and less mistakes because of the team being unified under one
company or contract. The stakeholder must be clear with their goals in the early program
and communication throughout the project. Without a clear vision there will be scope
ambiguities and potential scope creep and it will be difficult for the EPC firm to plan,
monitor, and control the project. The main disadvantage for the stakeholder will be less
design control.
The success of the EPC firm will depend on the robustness of their planning and
scheduling, which will reduce confusion and conflicts in the field where the costs for rework
https://source.aacei.org/2021/10/05/successful-design-scheduling/
6/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
are much higher than costs of design changes earlier in the process.
Design-Build – Stakeholder to ~30%, Contractor ~30% to 100%
Design-build delivery method in commercial projects is similar to the EPC delivery method,
however, this concept is commonly used in many industries outside of the EPC process
world, particularly as a means to shorten the construction duration and limit risks to the
stakeholder for performance. The stakeholder details the drawings to the point at which it
defines the scope of work without eliminating opportunities for innovative design by the
contractor. The documents that the stakeholder prepares for use in bidding and procuring
the contractors are often called “bridging documents” or the “program definition”
documents. The contractor includes the detailed design firm on the DB contractor team, so
there is a more engineering-construction integrated approach to design. The contractor can
detail the design in specific scopes of work to the point at which it allows construction to
proceed, and it accommodates early release of some design packages, advancing the
construction. An industry term for this staged release of early trade contract work packages
is often called “fast-track” construction, and there are implementations relying on fast-track
delivery such as “advanced work packaging” that formalize the effort and helps improve the
quality of the transition to construction.
CM at Risk (CMAR) Project Delivery – Stakeholder to 100% with CMAR Providing Project
Controls
With CMAR delivery, the CM acts in the interests of the stakeholder, providing project
controls expertise and construction experience to help monitor design by VE,
constructability reviews, estimating, and scheduling. This allows the CMAR to coordinate
with the designers to plan and schedule early trade contractor work in packages that allow
construction to start earlier than would be possible with full design required before bidding.
This method is commonly contracted on a cost-plus-a-fee in the early stages to enable the
CMAR to provide these services, but most often, converts to a fixed fee for a fixed duration
contract once the scope definition has advanced sufficiently for an accurate bid. Risks to
the stakeholder lie in the reputation and competence of the CMAR, as well as the full
engagement of the CMAR in validating the budget and schedule of the design as it
matures. However, with an experienced and competent CMAR, the project can sequence
trade work and shorten the duration while minimizing stakeholder risk. Once the CMAR is
willing to convert to the fixed price and duration, his role is more akin to a traditional general
contractor, taking on all the risk of performance.
Alignment of Design Stages and Project Controls with Project Delivery Method
https://source.aacei.org/2021/10/05/successful-design-scheduling/
7/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Designs mature through the design phases and so project controls services must track with
estimates and schedules aligned by the level of scope definition and the usage of the
budget and schedule. The characteristics of the estimates and schedules and the
alignment with scope definition are best explained in the AACE International recommended
practices for cost and schedule classes. [References 2 and 3, (page 3 in both
publications)].
Pre-Design Phase
In the pre-design phase, there are no drawings to define the scope of work. The project is
defined by a statement of work or other narrative description of the project. Estimates and
schedules are very high-level, providing analogous or parametric level products with a wide
range of accuracy to the lack of scope definition. AACE Class 5 estimates are typically
provided during this phase, as well as AACE Class 5 schedules. However, these early
budgets and schedules are the beginning of the benchmarks against which the project will
be monitored and analyzed, so it is vital that pre-design phase estimating and scheduling is
appropriate and reasonable.
At this stage, value planning is useful as it helps provide guidelines as the project moves
into early design using appropriate techniques and products for the location and industry.
The delivery method at this phase has generally not been determined so the project
controls services are typically provided by the stakeholder, whether in-house or by
consultant. Engaging the project controls professionals during pre-design provides
guidance in selecting an appropriate project delivery method and is a strong indicator of a
successful project.
Concept Phase of Scope Definition
In this phase, project controls services continue to be comprised primarily of developing
conceptual budgets in the form of capacity factored or parametric modeled AACE Class 5
concept screening estimates, preliminary schedules in the form of AACE Class 5 concept
screening milestone schedules, and value planning to help determine the construction
means and methods. In some industries, when the professionals providing estimating and
project durations have extensive experience and benchmarked databases, the range of
accuracy can be narrowed for both budget and schedule, which reduces risks during later
phases.
Design Phase
In the preliminary design phase, there are likely to be sketches, plan layouts, line drawings,
and site concepts. However, as design progresses through this phase, further development
will result in much more detailed drawings. The design phase is divided into sub-phases
https://source.aacei.org/2021/10/05/successful-design-scheduling/
8/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
based on design development progress stages. Good practices suggest that completion of
each phase should result in a thorough cost, schedule, risk, and scope review to ensure
that the design is progressing satisfactorily and can be built using efficient techniques, at
the cost specified in the budget, and within the planned project duration. With the stagegate process, the design engineering halts until the cost, schedule, risk, and scope review
verifies that the design still fits to the budget and project duration.
Concept Development – to 15%
In this phase, project controls services are comprised primarily of developing study budgets
in the form of equipment factored or parametric modeled AACE Class 4 estimates [1] for
study or feasibility purposes, planning milestone and project events AACE Class 4
schedules [2] for feasibility study purposes. During this phase, scope definition is primarily
still the responsibility of the owner.
Design work is an iterative process. As a result of the nature of this work there is a
tendency to only want to track hand-offs between disciplines in the schedule for all the
phases, especially the conceptual phase. However, the more detail in the inter-discipline
relationships, the better. The best practice is to plan for the known scope then adjust as the
details become clearer. Tracking only hand-offs never yields an accurate schedule or a
schedule that can be tracked and reported on in a valuable way. In schedules that only
track hand-offs the logic ends up needing to constantly change to match what is really
going on, which is unnecessary work. Planning for the known scope, then making
adjustments, also helps in successive phases because the teams may change (and
probably will), but if the new team can see what happened in the previous phases in detail,
then they can avoid unnecessary rework.
Schematic/Scoping – 15% to 30% (FEED 2 Package)
In the 30% maturity of scope definition, the design phase is likely to be the start of detailed
design documents, providing more scope definition. Project controls in this phase are
comprised primarily of developing sanction budgets once again in the form of budget
authorization AACE Class 4-unit cost and line-item estimates, and more detailed planning
AACE Class 3 authorization or sanction schedules [2]. At this point in the scope definition
maturity, the responsibility for design depends on the project delivery method, as noted
above. However, the discussion here about the project controls services supporting design
monitoring may be provided by the owner, the A/E, a consultant to the owner, or the
contractor when the delivery is design-build or EPC.
During the approximate 15% to 30% design, commonly referred to the schematic and
preliminary design stages of the design, the key opportunity is to ensure the design is
beginning to align design deliverables with the construction schedule needs. The CPM
https://source.aacei.org/2021/10/05/successful-design-scheduling/
9/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
schedule can now start to support further refinement of the deliverables and specify how
interim design stages will be monitored and tracked. One of the goals and focuses during
this stage of scheduling for design should be establishing design definable features of work
for the major deliverables.
Establishing these interim design features of work deliverables can help to:
Define task flow through each major deliverable
Establish critical path dependencies necessary to drive a design deliverable to
completion
Help alert the project team to specific needs required by one another.
As discussed earlier in this article, key design deliverables are typically tracked to certain
percentages throughout the life of the design, but the problem is assigning progress to
these percentages. To successfully do this, decisions need to be made as to what
percentages apply to disciplines at each stage gate. It is during this stage of design that the
designer should include additional design players, i.e., sub-consultants, out-side agencies,
or the technical team to collaboratively discuss roles and responsibilities as it relates to the
design and schedule. It is important during this early stage to collaboratively agree on
interim design delivery milestones to help ensure clear deadlines providing scope definition
for each related discipline. These discipline-specific scope definition completion
percentages should be used in scheduling.
During the conceptual design stage, a milestone schedule was developed to establish the
major deliverables. This stage of design is where the schedule should start to move from
conceptual/milestone driven to evolve into a more detailed logically driven schedule that
contains these discipline-specific scope definition completion percentages.
See the following list for some possible expected design submittals goals during the 15%
and 30% stages that can influence the schedule planning:
15% (Schematic Design)
Develop design draft schematics and concept layouts
Initial opinions of probable construction costs
Determine that the concept is consistent with the design budget
30% (Preliminary Design)
Finalize basis of design and advance spatial design
Design is suitable for an initial constructability review
Begin drafting the project manual
https://source.aacei.org/2021/10/05/successful-design-scheduling/
10/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
The 30% preliminary design phase is also the stage where not only the design schedule
criteria is developed, but the construction implementation of the project should also start to
be included in the project schedule. This should help the design team better understand
how the project will likely be constructed with insight provided by experienced construction
managers (CM). This will of course require involvement of CMs to assist the project team in
bringing their construction background to the table. Their input early in the design process
will beneficially impact design, ultimately yielding a better, more efficient, and more
complete design, as well as promoting early resolution of design problems before impacting
the schedule.
Planning to support the design submittal goals occurs during this stage; with products such
as contract time determination, schedules used to establish contract delivery dates, and
pre-bid contractor’s schedules from a select group of approved contractors to help align the
construction with early design. These schedules will need to be reviewed by the
stakeholder and are used for confirmation of procurement decisions and to start monitoring
progress at the various stages to ensure they are on track either through durations or
interim milestones.
Another often overlooked value to the design schedule at this stage is to start to establish
critical paths through the design criteria so the CPM schedule can ensure contributing
disciplines provide their submittals on time to allow successor design to proceed. This effort
will increase in later stages as more detailed designs are developed.
Collaboratively establishing design deliverables will significantly improve the quality and
efficiency during this design stage. While this stage of design is still relatively early,
construction and schedule input now could lead to significant value engineering savings
that would not affect bidding documents.
Design Development – 30% to 50% (FEED 3 Package)
In the 50% maturity of scope definition, the design will be expanded to more detailed
drawings in multiple disciplines, requiring considerably more coordination between the
disciplines. Project controls in this phase are comprised primarily of developing control
budgets in the form of control AACE Class 2 estimates [1] providing detailed unit cost and
line-item take-off estimates and bottom-up planning AACE Class 2 schedules [2] for control
or bid/tender use. These estimates and schedules are provided by different entities based
on the project delivery method. For design-bid-build, the owner still has the responsibility
and provides the integrated project controls support, either in-house or with a consultant,
for CMAR, the CMAR provides the support sometimes with the owner providing a program
or construction manager to validate the results, and with design-build or EPC, the
contractor starts to pick up the integrated project controls support to their own design effort.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
11/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
These responsibilities for the integrated project controls services are consistent through the
rest of the stages of design maturity.
Construction Documents – 50% to 80%
As the design matures from 50 to approximately 80% complete scope definition, the design
is being finalized, disciplines are coordinated in a feedback loop, quality control is
implemented with check sets and/or building information modeling with 3D drawings.
Project controls in this phase are comprised primarily of developing check estimate budgets
in the form of bid/tender Class 1 detailed unit cost with detailed take-off estimates at the
same level of detail as contractor bid documents, producing detailed planning Class 2 or
possibly Class 1 bid/tender control schedules [2].
Bid/Tender Documents – 80% to 100%
The goal of this design stage is typically to produce a complete set of drawings and
specifications that have passed internal quality control and coordination and are ready for
construction. The design is suitable for final client review, permit application and allows an
opinion of probable construction cost and project contractual duration that will serve for
review and selection of the contractor. This is also the stage for a final bid document review
to ensure everything aligns with stakeholder and third-party requirements. Lastly, the final
goal is to publish the bid documents and supplemental information for the market.
Depending on the project delivery method, the responsibility for completing the design can
vary. The scheduling effort during this final stage will help ensure each of the design
package criteria is met with all submittals and is complete. Accurately modeling the final
stages can ensure all reviews or meetings are scheduled in advance to help ensure a
collaborative communication between all design team members or stakeholders.
Recommended Practices for Design Schedule Development
Phase-Gate Approach
The approach that is commonly called a phase-gate approach to project controls support
during design has proven success when followed appropriately (Phase Gate is addressed
by the Construction Industry Institute in discussions of Front-End Planning effort). This
approach uses the design development phases or stages noted above and recommends
the use of an approval gate at each stage. When the design has developed to match the
stage of scope definition, design is not allowed to proceed until a thorough review of the
cost, schedule, risk, constructability, and value engineering shows that the project is still
tracking within the target benchmark, opening the gate to allow design to proceed into the
next phase up to the next gate.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
12/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Figure 1–Phases and Gates from CII Front End Planning Process
Clear Program Definition
Clear understanding of the design statement of work or concept write-up is vital to
establishing the design definable features of work. This starts with the design package
criteria that clearly states each design submittal requirement; “The project will require 500
feet of pipe” is an example of a poorly defined feature. A better-defined example would be
that the project requires 500 linear feet of RCP and two drainage structures for adequate
site drainage across a specific area.
The scheduling effort will be less effective if the contractual requirements for the schedule
are vague and non-specific. Often, the schedule specifications clearly state the
requirements for construction, therefore a construction schedule is typically detailed to build
the project. So, the question needs to be asked: “Why can’t the schedule specifications
require similar level of detail to monitor and track design?”
The schedule specification is the stakeholder’s opportunity to ensure the designer monitors
progress appropriately for the full design effort. It is crucial that the design and construction
documents are well developed and clearly depict the stakeholder’s needs. This is
especially true for design-build, and CM at-risk type deliveries since most of the project risk
falls to the contractor, which can limit the reporting to a stakeholder. Generally, the
schedule is and will be one of the best communication tools between the designer and
stakeholder for all delivery methods. Therefore, a vague or non-specific schedule
specification can reduce the accuracy of information provided to the stakeholder. This tends
to lead to unreliable schedule predictions as well as over or underreported progress that
may lead to late design and design cost overruns. An appropriate schedule specification
should address the following items.
Establish Completion Milestones (Phase-Gates)
There is no single standard for the percentage of design completion at each milestone, so it
is vital that these are established to accommodate the needs for quality control review,
value planning and engineering, constructability review, budget and schedule review, and
risk assessment. Sometimes these milestones align with payments or are designed to
https://source.aacei.org/2021/10/05/successful-design-scheduling/
13/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
enable certain package releases. Establishing these milestones is important and should be
carefully reviewed by the team to ensure that the scope of design work required by each
milestone is defined and understood. With the appropriate definition and team
understanding, progress monitoring is improved to allow successful design at the
appropriate time for the expected project duration.
Define Detailed Scope Required before Each Milestone (Phases)
Once the phase-gate completion milestones are established, the detailed scope required to
be completed in each phase must be identified. There should be milestones for each
phase, they could be in the form of deliverables. It may be an approval package or a
submittal depending on the phase. The requirements for each milestone must be
specifically identified and the level of quality outlined. Note that depending on the project
delivery method, the stakeholder responsible for accepting the final design package might
be the stakeholder or the contractor.
Document Specific Completion Definitions to Support Project Controls Review
For this approach to work well, it is important that the milestones are well defined so
monitoring the completion of each phase-gate milestone is straightforward and simple. This
is a tougher problem than it should be because the cumulative percentage of completion for
any given milestone includes a wide variety of different levels of completion for many
disciplines. While a 30% design completion might show structural design as 60% complete,
commissioning may not have even started. No matter how progress is tracked, the
definition allows a good estimate and evaluation of completion. The authors have found
that resource loading of the schedule using design hours and costs is the best approach
when the designer team participates. However, when the designer is not cooperative in
establishing discipline hours and costs, there are other simple implementations of progress
monitoring, such as earned value based on the number of drawing sheets, which can still
be useful. No matter the progress monitoring, the stakeholder must specify completion
goals and the designer still must identify which sheets must be complete to achieve the
gate milestone terminating each phase.
The scheduler should meet with the designers, get a list of all the disciplines that must be
completed to meet the milestones, and then determine with the designers how mature each
discipline must be at each milestone. Developing a clear definition of each milestone with
detailed understanding of the maturity of each discipline is vital to implementing this
approach.
Key Risks in Design Schedule Development
Poor or little validation of the key design milestone completion percentages can often be
the primary contributing factor to a design submittal failure. Without the use of a stage-gate
https://source.aacei.org/2021/10/05/successful-design-scheduling/
14/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
approach to scheduling, a design firm’s progress monitoring of design deliverables can be
inconsistent and inaccurate. Often one design firm’s definition of 30% drawings is very
different from another firm’s idea of the 30% design submittal. Or, after submission of the
deliverable, the submitted package is only approvable to 20% complete based on design
criteria. These discrepancies can stem from a design firm’s inability to accurately model
and track to design submittal deliverables, which can affect cost, time and quality. The
following list of questions should be considered when updating and progressing the
planning design schedule:
What is the overall estimated completion percentage for the design package?
How will the deliverable milestones be measured, by money, or hours expended?
How are the design definable features of work developed?
Do the costs and hours in the activities in each submittal requirement equal the total
submittal budgeted cost/hour?
Do the activities clearly define the measurable deliverables?
What is the level of effort?
Is the schedule able to monitor the design milestones, i.e., 15%, 30%, 60%, 90%?
The importance of accurately modeling and updating the schedule can significantly
increase the reliability for the design submittal deliveries. This is achieved primarily through
the appropriate modeling of the activities and managing the stage-gate project controls
reviews to reach the overall submittal requirement. By appropriately validating each design
submittal milestone completion, potential issues should be identified and an acceptable
status for the submittal goal established.
Develop Activity Detail per Milestone
This will help define the specific activities included in the schedule that must be completed
before opening the gate to the next phase. This is the area where the A/E input is needed
because most A/Es have internal planning documents that suggest the disciplines and the
discipline completion that should be associated with each milestone. The scheduler will
need to collaboratively acquire this information and then validate it with the A/E team to
ensure an appropriate detailed design schedule that models the expected maturity of the
individual discipline documents.
Establish Resource Availability
Establishing design resource availability by discipline should be done after activities are
identified and sequenced, and then activity durations can be determined. A key part is
knowing what is needed (i.e., civil structural architectural (CSA), electrical &
instrumentation (E&I), process, plant design, mechanical), as well as knowing what level of
resource is needed (i.e., junior/senior level), to provide the expected design development.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
15/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Knowing the full design scope is paramount to acquiring the team needed. The next step
after establishing the scope is understanding the complexity of the scope to help the
designers determine the mix of senior and junior staff needed for the disciplines. Of course,
the designers will consider the risks of using junior personnel (i.e. increased durations,
quality of work) and evaluate those risks with the costs of more senior staff providing the
work.
Once the resources required are known, then the process of modeling staff availability can
begin. Once the resources are developed in the scheduling software, the next step is to
establish the discipline resource calendars. Later the team’s schedules can be incorporated
into the master schedule to ensure that all other required work is planned and monitored,
and performance in design work will be sufficient to maintain the program goals.
During the establishing of resource availability, consideration needs to be given to
construction equipment availability since the delivery will be a function of the approved
design releases for procurement. The design schedule should show any of these or other
long-lead procurement items that may have to be ordered or reserved during the design
phases to have it in time for the construction. With an accurate design schedule, the
stakeholder can determine if the schedule will allow for the selected contractor to order
these items or if the tight schedule might require the stakeholder to consider direct
purchase. These are decisions that should be evaluated as soon as possible after the
design schedule is approved.
Identify Time and Cost Budget (Load Hours and Costs)
Once milestones are defined and resources established, the resource loading is pretty
straightforward, except that it has to meet the milestone completion. This requires resource
loading the schedule, which is the individual discipline costs and hours broken down into
the work that is associated with each milestone definition.
Suggested Practices for Design Schedule Monitoring and Analysis
Enforce the Stage-Gate Approach
Monitoring of design is straightforward once the definitions are set up, so this step simply
requires adhering to the project controls services identified for each of disciplines. The
stage-gate approach to integrated project controls monitoring of design deliverables is
relevant to any of the project delivery methods. No matter whether the delivery is designbid-build where the owner is at risk for design, or CMAR, where the owner and CMAR
collaborate to minimize the risk of design, or design-build and EPC where the contractor
takes over and assumes full responsibility for design, the stage-gate approach improves
design durations and quality.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
16/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Monitor Design Progress at Activity Level
The main goals of accurately modeling and updating a construction CPM schedule are to
monitor progress, identify delays early enough to mitigate, provide corrective actions to
maintain planned progress, provide change management support, and avoid disputes in
construction. With design scheduling, the goals are reduced to monitor progress, provide
corrective actions to maintain planned progress, identify changes from the project controls
reviews, and provide change management support.
Much of this can be achieved through a combination of critical and near-critical path
analysis and CPM schedule trending analysis with design scheduling because design
combines a productivity effort with a sequencing effort; multiple teams take on the design
concurrently, but each team has cross-discipline relationships with the other teams that
drive delays across the disciplines. The trending analysis is most useful in activity
performance trending, such as duration overruns and plan adherence monitoring, rather
than just sheet count or earned value metric trending. The updated project schedule is the
primary monitoring tool for the project. It provides the benchmark for analysis of progress
and delays. Review and approval is the stakeholder’s opportunity to ensure a quality
update schedule that will serve as the model for analysis of change, trending and
completion predictions.
The first step in the update process, prior to any data input, is to gather the data. The
scheduler should provide the update report to the team and responsible parties at regularly
scheduled intervals based on the frequency of the update process. Suggested information
to provide in the update report or layout is: activity identification code, activity name,
original duration, remaining duration, percent complete, float, actual start, actual finish, with
a blank column for remarks.
One aspect of planning includes assigning specific roles and responsibilities for measuring
the progress and performance. During the schedule development process, the scheduler
should assign responsibility to each activity in the schedule. In Primavera P6™, this is
easily accomplished using an activity code (i.e., responsibility).
Using a responsibility activity code allows the scheduler to break down activity progress by
the discipline or individual performing or responsible for the work. Each responsible party
can, by organized use of filters and layouts, review a report of work progress and effectively
plan for near term activities. The scheduler can then also more easily identify potential
issues and mitigate risks based on performance factors.
Use Earned Value Management
Since the design scheduling effort is heavily oriented to production and productivity along
https://source.aacei.org/2021/10/05/successful-design-scheduling/
17/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
with sequencing progress, monitoring is well served with a focus on the productivity and
production. A critical and near-critical path analysis ensures that delays are identified when
they occur, such as a failure of the architect to provide initial floor plan layout to the
structural engineer. Non-critical path delays can also occur, so it is important to monitor the
progress of all activities, including non-critical path activities.
The typical failures in design scheduling occur when cross-discipline hand-off dates are
missed, progress falls behind, or budgets start to overrun. With performance issues, too
often the designer simply redefines a poorly defined milestone to claim completion at the
planned level, say 30% completion. But when that milestone has been defined in detail,
that redefined 30% completion milestone is identified as more likely 20% or 25% and that
has serious ramifications for the range of accuracy of budgets and schedules associated
with that phase.
Monitor Hourly Earned Value for Progress
Architectural and engineering design is budgeted and monitored in hours, so loading the
schedule with hourly resources is relatively straightforward. There still is a decision to make
with respect to budgeting; if the firm has targeted specific designers, then there might be a
need to load individual resources, designers by name. This would allow for monitoring to
ensure that each person has the appropriate workload and will not be over allocated by the
schedule as performance is updated.
More commonly, hourly resources are loaded by roles; grouping individuals by levels or
types of roles such as Engineer, Senior Engineer, or perhaps Engineer Level II. The
premise is that anyone who carries the title, for the project, of one of the roles is
interchangeable with anyone else, so if four Engineers are Senior Engineers, the loading
would allow monitoring of over allocation of the group of Senior Engineers.
This role-based approach allows for a certain amount of flexibility and ensures that tasks
assigned to Engineers Level I will only be scheduled for the Engineers in that category, so it
is easier to maintain the budget. The loading and monitoring is also simplified since specific
person performance does not need to be reported.
Monitor Cost Earned Value for Efficiency/Productivity
Although monitoring hourly earned value works well, consumption of hours does not
necessarily relate to progress. While it is important to monitor hours, that does not indicate
the efficiency of the work, and with the likelihood that there is a range of salaries within
each role, the risk is that too many hours are consumed at the high end of the salary range.
The design firm needs the ability to recognize when they are at risk of exceeding budget
even when operating within the hourly totals for each phase.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
18/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
This risk can be managed by a loading of costs in addition to the resources into the
schedule. The cost-based earned value system can be used to monitor the productivity
while the hourly-based system monitors production. Running metrics from both loading will
help the design firm stay on schedule and budget.
Provide Critical and Near-Critical Path Analysis
Providing critical and near-critical path analysis is vital as it will ensure that the discipline
work that must be sequenced is managed and monitored. For example, the mechanical
engineer designing the plumbing system requires multiple input to proceed with 30%
preliminary design piping sizing, which might include:
Plumbing fixture requirements from the architect
Drainage requirements from the process engineer
Fuel-fired boiler information from the HVAC mechanical engineer
If the plumbing design cannot proceed without the necessary input, delays from the one
discipline can be magnified as other disciplines are unable to complete significant portions
needed for the team to meet the 30% preliminary design milestone.
Provide Trending Analysis
Trending analysis is the use of historical records to identify a pattern of production or
productivity results that will eventually cause cost and time overruns. These patterns are
often insidious and some areas are not easily identified without a detailed schedule used to
monitor performance.
An example of schedule trending is the duration overrun risk; if the structural steel
engineering has performed the first 25% of their scope in durations that are twice as long
as planned, analysis of that trend might show that continued performance at that same rate
will cause them to miss a stage-gate by 30 days. Those types of delays will be magnified
as they are driven into other disciplines waiting on the structural steel designs, and the
trending analysis requires the CPM schedule to determine the expected impact from the
delays.
Other trends are more productivity-based only, and could be managed without the
schedule, for example, if a project task required 400 sheets of engineering drawings and
committed to 40 days to complete engineering, that means the team must complete 10
sheets per day.
If they get 20 days into the task and have completed 100 sheets, they have completed 5
sheets/day. This trends to:
https://source.aacei.org/2021/10/05/successful-design-scheduling/
19/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
20 remaining days x 5 sheets/day = 100 sheets by day 40
100 sheets (complete) + 100 sheets (trend) = 200 total sheets by deadline
This performance would miss the target by 50%, AND, with proper tracking, scheduling and
stage gate milestones the overrun could have been prevented.
Provide Mitigation Needs and Opportunities
One of the benefits of a good scheduling effort is the ability to provide predictive analysis to
identify slippage in performance and budget, and the resulting corrective actions that can
be recommended to mitigate the delays. Done properly, this can allow the A/E to re-assign
resources to supplement or replace weak performers, ensure the right level of experience
in each task, and improve the achievement of the assigned level of completion stage.
The same is true of gains; analysis of schedule trending when there are improvements in
performance will show potential opportunities to improve delivery dates.
Conclusion
One of the common failures in construction programs is the timely production of
architectural and engineering drawings. This shows up as missed partial completion
milestones, under-designed milestones, late delivery of completed packages, and the risk
of incomplete packages that are released just to meet deadlines.
The further symptoms and risks from this failure revolves around the scheduling and
budgeting that is performed at the wrong range of accuracy because the documents are not
really completed to the appropriate level of detail in all disciplines. The range of accuracy is
dependent upon the maturity level of the documents, so inaccuracy in the level of
completion will limit the ability to produce a more accurate project duration (and budget) as
the design matures.
A commitment to thorough technical scheduling at a level of detail that allows appropriate
monitoring of production and productivity would improve design completion results, with the
accompanying improved ability to design-to-budget and schedule. Owners would benefit
from requiring and funding an integrated project controls design effort by reduced project
durations and lower costs, no matter the project delivery method.
The integrated project controls phase-gate effort has been proven to improve the
completeness of the deliverables and the confidence in the measured level of maturity of
those deliverables. [5]
https://source.aacei.org/2021/10/05/successful-design-scheduling/
20/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
While studies related to design performance rarely isolate scheduling of the design, CII has
a number of studies of assessments for measuring project scope definition and alignment
between project participants that have a strong scheduling component for design stages.
One of those studies notes that the index “allows its users to measure the level of scope
definition and to compare scope definition to anticipated project success.” This study
looked at a Project Definition Rating Index (PDRI), comprised of a number of contributing
factors which included the scope definition and appropriate maturity of the scope supported
by design scheduling, and found an average “Schedule reduction by 13 percent” in the
projects scoring higher in pre-project planning (all the design leading to detailed
engineering). [4]
This commitment to an accurate and detailed technical design schedule requires time and
costs to develop and monitor the schedule, but the authors have seen huge losses to A/E
firms due to designs that take considerably longer than planned and lead to unhappy
stakeholders. The costs to provide an integrated stage-gate project controls effort are much
less than many of these losses. All the stakeholders, whether owners, contractors, or
designers, would see benefits from spending the additional costs up front to provide this
effort.
REFERENCES
1. AACE International Recommended Practice No. 18R-97, “Cost Estimate
Classification System – As Applied in Engineering, Procurement, and Construction
for the Process Industries”, Revised March 1, 2016.
2. AACE International Recommended Practice No. 27R-03, “Schedule Classification
System,” Revised November 12, 2010.
3. AACE International, Recommended Practice 56R-08, “Cost Estimate Classification
System —As Applied in Engineering, Procurement, and Construction for the Building
and General Construction Industries,” Revised August 7, 2020.
4. Construction Industry Institute, “Pre-Project Planning Tool: PDRI for Buildings,”
1999.
5. Construction Industry Institute, CII Research Team 331, “Assessing the Maturity and
Accuracy of Front End Engineering Design (FEED) to Support Phase-Gate
Approvals,” 2017.
6. C.R.T. 331, “Assessing the Maturity and Accuracy of Front End Engineering Design
(FEED) to Support Phase-gate Approvals,” Construction Industry Institute (CII),
Austin, 2017.
7. DBIA, “Choosing A Project Delivery Method, A Design-Build Done Right Primer,”
Design-Build Institute of America, 2015.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
21/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
8. S.M. Report, “Managing Uncertainty and Expectations in Building Design and
Construction,” McGraw Hill Construction, 2014.
ABOUT THE AUTHORS
Christopher W. Carson, CEP DRMP PSP FAACE, is with Arcadis U.S., Inc. He can be
contacted by email at: chris.carson@arcadis.com
Aaron Fletcher, PSP, is with Arcadis U.S., Inc. He can be contacted by email at:
aaron.fletcher@arcadis.com
Noah A. Jones, PSP, is with Arcadis U.S., Inc. He can be contacted by email at:
njones@schiavone.net
Leo Carson-Penalosa is with Burns & McDonnell. He can be contacted by email at:
carson.penalosa@gmail.com
Rate this post
Click on a star to rate it!

Average rating 5 / 5. Vote count: 17
Share
← Previous Post
Next Post →
2 thoughts on “Successful Design Scheduling”
REGINO ESTEVEZ
OCTOBER 7, 2021 AT 12:31 PM
https://source.aacei.org/2021/10/05/successful-design-scheduling/
22/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Very interesting.
Reply
NED RODRÍGUEZ
OCTOBER 8, 2021 AT 8:35 AM
Excellent article, very complet. Thank you for sharing.
Regards
Reply
Leave a Comment
Your email address will not be published. Required fields are marked *
Type here..
Name*
Email*
Website
Save my name, email, and website in this browser for the next time I comment.
https://source.aacei.org/2021/10/05/successful-design-scheduling/
23/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
POST COMMENT »
https://source.aacei.org/2021/10/05/successful-design-scheduling/
24/25
9/18/23, 11:48 AM
Successful Design Scheduling - Source
Phone: 304.296.8444
About Us
AACE International
www.aacei.org
Connect




Copyright © 2023 AACE International
https://source.aacei.org/2021/10/05/successful-design-scheduling/
25/25