Rethinking Interface Management

PM World Journal (ISSN: 2330-4480) Rethinking Interface Management
Vol. X, Issue VIII – August 2021 by Bob Prieto
www.pmworldjournal.com Commentary
© 2021 Robert Prieto www.pmworldlibrary.net Page 1 of 13
Rethinking Interface Management1
Bob Prieto
Introduction
Today’s infrastructure and facilities are “smart”. At least that is our objective as we seek to
enhance lifecycle performance and capital efficiency. These “smart” facilities transcend any
given sector and bring new challenges to the engineering and construction industry. In some
ways our more traditional projects are today outcomes focused or capabilities delivering IT
projects with bits of concrete and steel wrapped around them!
This “smart” focus is not limited to just a technology and systems dimension but goes further,
demanding an increased and increasing environmental, social and governance (ESG)iii
focus as well. Together “smart” and ESG create a greatly expanded set of interfaces for
program and project managers to manage. These interfaces, both familiar and new, include:
• Physical
o Systems, structures, components (existing and new)
o Supply chain and logistical
o Intermediate and final states
• Digital
o Information/signaling
o Digital twin (design and construction models)
o Operating models
o Enterprise asset models
• Human
o Users (internal to project execution team)
o Stakeholdersiii (External to project execution team)
• Governanceiv, management, and decision making
o Communication
o Contractual – recognize that interfaces may span many contracts and
agreements
o Regulatory and reporting
These interfaces require changed perspectives with respect to:
• Constraintsv, emerging and changing over time
• Assumptions, activity and timing sensitive, also changing over time
1
How to cite this work: Prieto, R. (2021). Rethinking Interface Management, PM World Journal, Vol. X, Issue VIII,
August.

• Couplingvi (immediate and lagged)
• Life cycle phase (planning; engineering; construction; startup and testing;
commissioning; operating, including maintenance; end of life/decommissioning)
Importantly, these interfaces include both direct and nested interfaces. Additionally, a
system of systems perspective must pervade our thinking recognizing that many of the
elements above are themselves part of other, broader systems.
Interface management in this expanded context requires increased attention and different
constructs to prior interface management efforts primarily focused on physical or other more
direct, one-to-one interfaces. The complexity of interface management requires a step
change.
What is interface management?
Interface management includes all the activities associated with identifying, defining,
characterizing, controlling, confirming, and communicating information to enable distinct
objects, activities and actions to function in a coordinated and complementary way, as
intended. This co-functioning should be value adding, efficient and effective. In the “smart”
and ESG contexts laid out above this requires interface management to support
interoperability in an increasingly dynamic and complex world.
Numerous industry interface management standards exist. This paper is focused on the
expansion in thinking required to deal with the expanding open system’s nature of large
complex projects especially those with growing “smart” and ESG requirements and
emergent outcomes.
Interface management goes beyond the traditional constructs or configuration management,
which focuses on consistency of attributes through a system or components lifecycle. In
today’s increasingly complex world with increasingly complex projects we must recognize
that desired outcomes themselves are emergent and as such interface management must
ensure that appropriate value adding relationships are sustained even in complexity.
While interface management must still ensure that all information required to enable co-
functionality is present, its role in using various interface performance attributes as
constraints is modified with the addition of “smart” and ESG considerations. The number of
interface dimensions is greatly expanded, and interface management is the process to bring
the various bits of the project together to achieve the desired outcomes or capability
additions.
Nested interfaces
Nested interfaces have always existed in interface management but take on new importance
and challenges as today’s projects become “smarter” and address expanded environmental,

social and governance needs. In addition, a growing emphasis on pre-assembly and
modularization create a new layer of interface management for physical interfaces. Similar
modular approaches are found within the digital realm as knowledge assemblies develop.
Finally, many of today’s projects, while complex often layered systems in their own rights,
are merely one system in an even broader system of systems context.
Special attention must be paid to nested interfaces, ensuring that they are absorbed by other
interfaces and not neglected either unintentionally or by organizational design. Neglected
interfaces lead to degraded project lifecycle performance.
How does the interface management process change?
The traditional interface management process begins with a definition of interface
requirements from users, system, and program designers. As the project evolves interface
changes arising from technical and project requirements are managed utilizing a set of
interface management procedures that work hand-in-hand with configuration and change
management processes. Traditional interface management occurs at a work breakdown
level (WBS) and occurs as various systems, structures and components are integrated
within a WBS element as well as the integration of WBS elements in the project. Positive
control is exerted on interfaces and interface management reports capture these efforts and
provide input into configuration management and change control when requirements have
changed.
As we move into a project setting where “smart” interfaces become more dominant and ESG
interfaces take on an increased importance, traditional interface management processes are
found lacking. An expanded interface management process must include several added
considerations. These include:
• Moving beyond traditional interface parameters that specify location (x, y, z
coordinates); material properties at the interface (material specification (material
composition/alloy; thickness; pressure/temperature ratings); coupling related
requirements (weld type/electrical/ I&C coupler type; cleaning requirements; weld or
coupler materials and ratings)); and flow characteristics (fluid/current properties).
• Incorporating the various digital characteristics associated with physical interfaces.
These could relate to associated digital twin properties; control points or systems in
automated information, signaling and command and control system operating
features; digital information required for effective asset management systems. We
may think of this as meta data that is now associated with physical elements not just
the systems information flows. This is important since information flows have
increased interfaces with the characteristics, properties, and performance of various
system components.

• ESG interfaces that are becoming increasingly more pervasive into lifecycle project
systems. Examples for each of the components of ESG include:
o Environmental – embedded carbon; water footprint; end of life disposal
considerations
o Social – flow down diversity and local sourcing requirements; modern day
slavery requirements
o Governance – Buy America; sub-tier sourcing from embargo countries
This ESG metadata becomes integral to the interfaces at lower and lower levels.
• Substitution of the uncertaintiesvii associated with human interfaces especially in
control loops with the probabilistic (vs deterministic) actions of artificial intelligence
(AI)viii ix x xi and machine learning.
• Addressing the changing nature of interfaces driven by:
o Changed stakeholder requirements and agreements (these may include
changed regulatory requirements or even joint venture agreementsxii xiii xiv)
o Changed externalities (market; technological)
o Operating environment and broader system performance (transportation,
water, electrical and other network performance that act to modify interface
requirements either with respect to initial asset deployment or in an operating
environment)
o Component substitution from that initially specified
This is akin to metadata being represented as a function of time – meta(t).
• While interface management focuses on direct interfaces as well as those which
may be cascaded down, there are two other interface criteria worth calling out:
o Constraint couplingxv – this is an indirect interface where changes in one
element or activity causes modification in an interfacing element associated
with another element or activity.
o Assumptions may also be thought of as interface criteria. As such
“assumption migration” becomes an area of interface management concern.
Figure 1 illustrates the expansion of traditional interface management stages (design,
construction, operations and maintenance) and the associated physical properties that
traditionally defined interface parameters to now include the growing digital project
(simulation/scenario optimization, BIM/digital twin, enterprise asset management).
Governance addresses the myriad of organizational interfaces. We are heavily dominated
by a reductionist view of interfaces but the lifecycle perspective we see on more and more
projects necessitates a stronger eye on the holistic outcomes we desire. We will see later
that the strong addition of “smart” and ESG considerations further drives this holistic view
and increases the importance of governance as reductionist and holistic views must both be
satisfied.

Lifecycle Project
Operations &
Maintenance
Physical
Properties
Design
Construction
Governance
Enterprise Asset
Management
BIM/ Digital
Twin
Simulation
Scenario
Optimization
Holistic Frame
Reductionist
Frame
Information Flows
Figure 1
The systems challenge
We see the expanded nature of our project system with the introduction of “smart” and ESG
considerations. But the system’s challenge is compounded by the further expansion of our
system from a more closed system to one that is increasingly an openxvi one. Interface
management in an open system is one which battles emergence at every stage.
Documentation of system boundaries becomes more notional than the well bounded

traditional approach to interface management would allow for. As such the clarity required
for determining where interfaces exist becomes opaquer and even when we believe that we
have comprehensively defined them, new ones may emerge.
The systems challenge can only be met if we initiate interface management at the basis of
designxvii xviii stage when we are first defining requirements. It is here that the special
requirements that interfaces must accommodate first begin to emerge. It is here where the
discussions on “smart” integration into the basic project concept and our commitments to
ESG can shape our approach to interface management and the process and procedures we
put into place.
Interface control “documentation”
Interface requirements documents begin development at the basis of design stage. In
addition to the digital elements which are now central to definition of systems, structures,
and components we must now incorporate our ESG requirements from a documentation
and flow down perspective, not just a setpoint perspective. Importantly these interface
requirements documents must now encompass the full project lifecycle and do so from a
triple bottom line perspective. Assumption registers must begin development and the
relationships of assumptions to various interface points and criteria documented. Tracking
of assumption migration now gains a tighter link with the project’s change control process.
Traditional interface control drawings representing physical and control interfaces (P&IDs
for example) must be complemented by information flow diagrams, logic diagrams,
incorporated algorithms (to be tracked as they may evolve over a project’s lifecycle), and
BIM and enterprise asset management system metadata. Interface control documents aim
to clearly communicate all potential actions and interactions whether they are internal to a
system, structure, component (or their digital twins) or transparent to external users and
stakeholders. This interface control documentation increasingly is database driven and
model-based interface management will likely be required to address these expanded
interface considerations.
Interface data definitions become greatly expanded and the number of organizational
elements involved in effective interface control likely becomes all encompassing. The
challenge of interface control has grown exponentially but new tools such as artificial
intelligence and model-based approaches to interface management may make the
impossible practical. The introduction of biasxix xx xxi xxii in both AI and model-based interface
management must be avoided.
In the open systemsxxiii xxiv xxvcontext we are likely to find ourselves in, we may discover that
there are sets of changes at interface points which are beyond the project team’s ability to
control or limit. The interface management function now shifts to early identification of such
potential interface impacts (anticipating is desirable), assessing the range of impacts,
choosing a timely response to optimize outcomes within this changed context, and ensuring

all aspects of the interface have been addressed in responding to what may be an imposed
change.
Additionally, project flowsxxvi, their anticipation and identification, become ever changing
aspects of what now must be model-based interface management. As such, interface control
documents must extend descriptions of interfaces and interface types and specifically
describe how information is communicated within a subsystem or WBS; across subsystems
or various WBS; with external systems or project elements or other related projects; and its
ultimate users and stakeholders. This may be accomplished by layering of interface control
information, providing for different views of the project system as shown in Figure 2.
ESG
Systeme Performance (SMART)
Governance
Command & Control
Information
Simulation
Physical Properties
Enterprise Asset
Management
Digital Twin
Project Management
Reductionist
View
Holistic
View
Figure 2

As seen in Figure 2, ESG and system performance interfaces are principally contributors to,
and drivers of the requisite outcomes-focused holistic view. Information and physical
properties benefit from a reductionist view providing necessary granularity for interface
management.
Governance, project management, and command and control integrate these two views to
deliver the level of interface management these increasingly complex projects require.
Project management addresses the traditional interfaces one would expect related to scope
(addressing both outcomes and outputs), schedule (engineering, supply chain and
construction physical and temporal interfaces together with attendant information flows),
cost (assumptions and their migration; required characterizations to be achieved (Buy
America; various set asides)), risk (importantly including emergent risk including those
associated with correlation and coupling), effective integration (a primary focus of interface
management), and change management, recognizing the multi-dimensional, multi-level
effects of neglected interfaces or inadequate synchronization of the various project activities.
Best practices
Consideration of this changed and greatly expanded interface management role and
perspective is supported by adopting select best practices:
• Governance is essential, especially as system complexity and abstraction grow. It
must evolve throughout the full lifecycle of infrastructure and facility assets.
• Interface management frameworks and processes must be established at the outset
of development of a future operating asset and fully engage all stakeholders. All too
often stakeholder roles in interface management are added almost as after
thoughts.
• Establish interface management KPIs early in the project and focus on progress of
completing interface definitions and agreements.
• Match interface management frameworks with project complexity. Not too complex;
comprehensive enough; rather just right. Modular open systems approaches
provide flexibility in projects where technology development is an important element
and also in long lived assets which may undergo many stakeholder or technology
driven revisions over the course of their lifetimes.
• Ensure interfaces are sufficiently defined with clarity and acceptance on each side
of the interface. Standards should be used where possible, or context ones defined
and agreed to.

• Interfaces must be trusted. This is slowly earned but quickly lost. Measure the
effectiveness of interfaces in delivering the requisite value desired. Do “smart”
systems have the information they need to operate and continuously improve their
efficiency and effectiveness? Are ESG commitments being met and importantly,
communicated, frequently for ESG interfaces with various stakeholders? Is the
provided information satisfactory and trusted? Engage stakeholders continuously.
• Define interfaces clearly and comprehensively so that the information at these
points may be used for added, often emergent, purposes. Interfaces should convey
the rationale from design decisions and tradeoffs. Recognize that interface
decisions introduce system constraints.
• Interface management must facilitate concurrent but correlated project development
efforts providing clarity on interdependencies that are sources of uncertainty and
risk.
• Interface management must support cross domain interfaces. This is even more
important as the range of domains is expanded by the introduction of “smart”
technologies and expanded ESG requirements. Even in more traditional interface
areas cross domain interface management is often found lacking.
• Interface management must support synchronization across WBS elements,
interface layers and broader stakeholders.
• Both holistic and reductionist models of interfaces must be accommodated with
each adding value in different domains (higher and lower levels of abstraction).
Verify that models are fit for purpose.
• Interface management must support virtual (digital twin) project development and
operation throughout its full lifecycle.
• Ensure interface points are user-friendly, logical and useful. Do not make it overly
complex. Ascertain the utility associated with various interface points. Are they
value adding? You may be surprised how many are not.
• Test, validate and verify that interfaces ensuring sub-tier interfaces have not been
neglected and the trust earned is well founded.
• Ensure interface information is broadly available within the project team and others.
Avoid reinventing the wheel or setting up competing, or worse, conflicting interfaces.
Electronic workflow systems support interface management and tracking.

• Recognize and capitalize on the risk and performance insights available from
interface management KPIs.
Concluding thoughts
Recognize that each of the various levels and perspectives associated with interface
management provides a valuable insight into the project. Each level of interfaces and each
perspective is just a simplified abstraction of the system and its performance characteristics.
A fuller view is only gained through the sum of all these levels and perspectives and even
this is just an abstraction of the fullness of the project system. How these views link and how
they individually interact with each other and evolve over time is the real prize.
Interface management is more about informed decision making than absolute control of
interfaces as desirable as this may be. More holistic models with higher level interface
definitions aid in decision making, outcomes achievement, system optimization and
prediction of system behaviors and performance. Conversely the more detailed reductionist
interface definitions are essential for more traditional interface management. The
introduction of “smart” systems and ESG requirements requires that both holistic models
and the more traditional reductionist ones coexist.
As the physical configuration of the project takes shape based on an expanded basis of
design and accompanying technical design requirements, focus must shift to the various
other interface parameters such as those associated with digital and ESG parameters to fix
a set of higher-level design and interface criteria. These support the advancement of design
and analysis efforts, but the more holistic relationships must not be lost.

About the Author
Bob Prieto
Chairman & CEO
Strategic Program Management, LLC
Jupiter, Florida, USA
Bob Prieto is a senior executive effective in shaping and executing business strategy and a
recognized leader within the infrastructure, engineering and construction industries. Currently Bob
heads his own management consulting practice, Strategic Program Management LLC. He
previously served as a senior vice president of Fluor, one of the largest engineering and
construction companies in the world. He focuses on the development and delivery of large,
complex projects worldwide and consults with owners across all market sectors in the
development of programmatic delivery strategies. He is author of nine books including “Strategic
Program Management”, “The Giga Factor: Program Management in the Engineering and
Construction Industry”, “Application of Life Cycle Analysis in the Capital Assets Industry”, “Capital
Efficiency: Pull All the Levers” and, most recently, “Theory of Management of Large Complex
Projects” published by the Construction Management Association of America (CMAA) as well as
over 800 other papers and presentations.
Bob is an Independent Member of the Shareholder Committee of Mott MacDonald and a member
of the board of Dar al Riyadh. He is a member of the ASCE Industry Leaders Council, National
Academy of Construction, a Fellow of the Construction Management Association of America and
member of several university departmental and campus advisory boards. Bob served until 2006
as a U.S. presidential appointee to the Asia Pacific Economic Cooperation (APEC) Business
Advisory Council (ABAC), working with U.S. and Asia-Pacific business leaders to shape the
framework for trade and economic growth. He is a member of the Millennium Challenge
Corporation advisory board where he had previously served. He had previously served as both
as Chairman of the Engineering and Construction Governors of the World Economic Forum and
co-chair of the infrastructure task force formed after September 11th by the New York City
Chamber of Commerce. Previously, he served as Chairman at Parsons Brinckerhoff (PB) and a
non-executive director of Cardno (ASX)
Bob serves as an honorary global advisor for the PM World Journal and Library and can be
contacted at rpstrategic@comcast.net.

End Notes
i
Prieto, R. (2021). Reversing Global Warming; PM World Journal, Vol. X, Issue III, March;
https://pmworldlibrary.net/wp-content/uploads/2021/03/pmwj103-Mar2021-Prieto-Reversing-Global-
Warming.pdf
ii
Prieto, R. (2012). Application Of Life Cycle Analysis in the Capital Assets Industry; Second Edition; PM
World Journal, Vol. X, Issue II, February 2021; https://pmworldlibrary.net/wp-
content/uploads/2021/02/pmwj102-Feb2021-Prieto-life-cycle-analysis-in-capital-assets-industry.pdf
iii
Stakeholder Management in Large Engineering & Construction Programs; PM World Today; October 2011
iv
Prieto, R. (2021). Governance: Key to Successful Program Management Delivery; PM World Journal;
Second Edition; May; https://pmworldlibrary.net/wp-content/uploads/2021/05/pmwj105-May2021-Prieto-
Governance-the-key-to-successful-progam-management-delivery-2nd-ed.pdf
v
Assumption Risk Driver and Constraint Tracking; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/340949729_Assumption_Risk_Driver_and_Constraint_Tracking
_Key_Points
vi
Coupling in Large Complex Projects; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/342452306_Large_Complex_Projects_Coupling_in_Large_Comp
lex_Projects_Key_Points
vii
Prieto, R. (2020). Decision Making Under Uncertainty; PM World Journal; Vol IX, Issue XI – November
2020; https://pmworldlibrary.net/wp-content/uploads/2020/11/pmwj99-Nov2020-Prieto-Decision-Making-
Under-Uncertainty.pdf
viii
Prieto, R. (2019). Impacts of Artificial Intelligence on Management of Large Complex Projects. PM World
Journal, Vol. VIII, Issue V, June; https://pmworldlibrary.net/wp-content/uploads/2019/06/pmwj82-
Jun2019-Prieto-Impacts-of-Artificial-Intelligence-on-Management-of-Large-Complex-Projects.pdf
ix
Prieto, R. (2019). Proper Reliance on Artificial Intelligence in Project Management; PM World Journal, Vol.
VIII, Issue VIII, September; https://pmworldlibrary.net/wp-content/uploads/2019/09/pmwj85-Sep2019-
Prieto-proper-reliance-on-artificial-intelligence-for-project-management.pdf
x
Impacts of Artificial Intelligence on Management of Large Complex Projects; National Academy of
Construction Executive Insight;
https://www.researchgate.net/publication/340949660_Impacts_of_Artificial_Intelligence_on_Managemen
t_of_Large_Complex_Projects_1_Key_Points-Prieto-Impacts-of-Artificial-_Intelligence-on-Management-of-
Large-Complex-Projectspdf
xi
Proper Reliance on Artificial Intelligence in Project Management; National Academy of Construction
Executive Insight;
https://www.researchgate.net/publication/340949839_Proper_Reliance_on_Artificial_Intelligence_in_Proj
ect_Management_Key_Points
xii
Mega Project Joint Ventures; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/342448225_Mega_Project_Joint_Ventures_Key_Points
xiii
Joint Ventures in the Engineering & Construction Industry; Capital Projects Symposium; CMAA; May 5,
2014
xiv
Prieto, R. (2013). A Look at Joint Ventures; PM World Journal; Vol. II, Issue III – March 2013;
https://pmworldlibrary.net/wp-content/uploads/2013/03/pmwj8-mar2013-prieto-look-at-joint-ventures-
featured-paper.pdf

xv
Coupling in Large Complex Projects; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/342452306_Large_Complex_Projects_Coupling_in_Large_Comp
lex_Projects_Key_Points
xvi
Large Complex Programs as Open Systems; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/348690977_Large_Complex_Programs_as_Open_Systems_Key_
Points
xvii
Business Basis of Design; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/340949572_Business_Basis_of_Design_Key_Points
xviii
Addressing Project Capital Efficiency through a Business Basis of Design; PM World Journal; April 2014
xix
Prieto, R. (2019). Artificial Intelligence Ethics in the Project Management and Civil Engineering Domains;
PM World Journal, Vol. VIII, Issue VII, August; https://pmworldlibrary.net/wp-
content/uploads/2019/08/pmwj84-Aug2019-Prieto-artificial-intelligence-ethics-in-project-management-
and-civil-engineering.pdf
xx
Artificial Intelligence Ethics in the Project Management and Civil Engineering Domains; National Academy
of Construction Executive Insight;
https://www.researchgate.net/publication/340949550_Artificial_Intelligence_Ethics_in_the_Project_Mana
gement_and_Civil_Engineering_Domains_Key_Points
xxi
Verification and Validation of Project Management Artificial Intelligence; National Academy of
Construction Executive Insight;
https://www.researchgate.net/publication/342452507_Verification_and_Validation_of_Project_Managem
ent_Artificial_Intelligence_Key_Points
xxii
CMAA Construction Management Advisor; Verification and Validation of Project Management Artificial
Intelligence; 12/20/20
xxiii
Large Complex Programs as Open Systems; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/348690977_Large_Complex_Programs_as_Open_Systems_Key_
Points
xxiv
Prieto, R. (2020). Application of Systems Lifecycle Processes to Large, Complex Engineering and
Construction Programs; PM World Journal (ISSN: 2330-4480); Vol. IX, Issue IX – October 2020;
https://pmworldlibrary.net/wp-content/uploads/2020/09/pmwj98-Oct2020-Prieto-Application-of-Systems-
Lifecycle-Processes-to-Large-complex-programs.pdf
xxv
Prieto, R. (2020). Systems Nature of Large Complex Programs; PM World Journal, Vol IX, Issue VIII,
August; https://pmworldlibrary.net/wp-content/uploads/2020/07/pmwj96-Aug2020-Prieto-Systems-
Nature-of-Large-Complex-Programs.pdf
xxvi
Flows in Large Complex Projects; National Academy of Construction Executive Insight;
https://www.researchgate.net/publication/344306324_Flows_on_Large_Complex_Projects

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