Harmonizing SCL D&D2 And AACE 29R-03: Complementary Frameworks For Forensic Delay Analysis In International Arbitration

Introduction

The Society of Construction Law Delay and Disruption Protocol 2nd Edition (SCL D&D2) and the Association for the Advancement of Cost Engineering Internation (AACEI) Forensic Schedule Analysis Recommended Practice (29R-03) are both widely recognized frameworks that guide experts in evaluating delay claims and conducting delay analysis in construction disputes, particularly in international arbitration. Despite their widespread adoption, some practitioners have expressed concerns that SCL D&D2 and 29R-03 present conflicting approaches, potentially complicating their application in complex delay and disruption claims. This paper refutes such concerns, demonstrating that the two protocols are not only compatible but also complementary. SCL D&D2 offers a principled framework for managing delay and disruption claims, emphasizing the importance of contemporaneous records, critical path analysis, and transparent methodologies.

In contrast, 29R-03 provides a detailed, technical roadmap for executing forensic schedule analyses, with a structured taxonomy of methodologies tailored to varying project complexities and data availability. By integrating the strategic oversight of SCL D&D2 with the technical precision of 29R-03, party-appointed experts can develop robust, defensible delay analyses that withstand scrutiny in arbitration. This paper elucidates the synergistic relationship between the protocols, offering practical insights into their combined application to enhance the credibility and efficacy of delay analyses in resolving intricate construction disputes. Furthermore, the publication explains how both protocols support part-appointed experts in being able to provide the most credible and defensible delay analysis to international tribunals.

Overview of the Two Protocols

SCL D&D Protocol (2nd Edition)

The SCL D&D2 was published by the SCL in February 2017.¹ The SCL D&D2 provides practical guidance for managing and analyzing delay and disruption claims in construction projects. It emphasizes proactive measures, such as the maintenance of contemporaneous records and the establishment of baseline programmes, to facilitate accurate post-event assessments.¹ Key tenets include the identification of critical paths, the apportionment of responsibility for delays, and recommendations for selecting methodologies that align with the project's evidential landscape. This protocol is especially attuned to the legal dimensions of disputes, promoting approaches that enhance arbitrability and judicial acceptance across jurisdictions, including under common law systems prevalent in international arbitration. Furthermore, the SCL D&D2 highlights some key delay analysis methodologies and summarizes the applicability of these methods in different circumstances, however, leaving the judgement call of which methodology to apply on the expert's shoulders.

AACE International 29R-03 (April 25, 2011 Revision)

In contrast, 29R-03, issued by the AACEI in April 2011, provides a more granular, methodological blueprint for forensic schedule analysis.² It categorizes various analytical techniques — ranging from observational methods like As-Planned vs. As-Built to modeled approaches such as Time Impact Analysis — into a structured taxonomy, complete with implementation guidelines, advantages, and limitations. This recommended practice is tailored for retrospective forensic applications, offering experts a systematic means to quantify delay impacts while accounting for variables like data quality and project complexity. Its focus on standardization makes it a cornerstone for technical precision in expert reports, particularly in quantifying the effects of delays in critical path method (CPM) schedules. Notably, 29R-03 addresses the nuances of concurrent delays through functional and literal theories, providing flexibility in apportionment that aligns with varying legal standards.

Purpose and Intent of the Protocols

Both the SCL D&D2 Protocol and the AACEI Recommended Practice 29R-03 were written and intended to be guidance documents instead of prescriptive documents that mandate strict compliance to their content. The SCL D&D2 Protocol clearly states that its objective is to "provide useful guidance on some of the common delay and disruption issues that arise on construction contracts" and its purpose is to provide a mechanism to help parties resolve project matters involving delay and/or disruption and to resolve disputes quickly.² The protocol also caveats that "users of the Protocol should apply its recommendations with common sense."³

In a similar vein, the AACEI Recommended Practice (RP) 29R-03's stated purpose is to "provide a unifying reference of basic technical principles and guidelines for the application of critical path method (CPM) scheduling in forensic schedule analysis."⁴ In addition, the RP "is not intended to establish a standard of practice, nor is it intended to be a prescriptive document applied without exception."⁵ Therefore, deviating from the recommended protocols is a judgement call that the analyst should make alone. A commonsense approach with professional judgement and competency with the subject matter is therefore required when reading and applying the RP. The RP further acknowledges that "forensic schedule analysis, like many other technical fields, is both a science and an art. As such, it relies upon professional judgment and expert opinion and usually requires many subjective decisions."⁶

Therefore, both protocols require the reader to apply them in conjunction with their own professional expertise on the subject matter of delay analysis and extension of time (EOT) claims. However, both protocols also advocate that an analyst does not deliberately adopt and quote sections from the protocols out of context to further a position that may be untenable to support.

Common Themes Between the Two Protocols

The figure below effectively illustrates the complementary relationship between the SCL D&D2 and AACEI's RP 29R-03 for Forensic Schedule Analysis, two pivotal frameworks in forensic delay analysis for construction disputes. The SCL D&D2 provides best practices and guiding principles for EOT and disruption claims, incorporating some forensic schedule analysis (FSA) methods to emphasize proactive management and legal considerations. 29R-03 is robust source of detailed requirements for implementing FSA methods, including a comprehensive taxonomy and method implementation protocols that offer technical rigor and standardization.

Figure 1: Commonalities Between SCL D&D2 and AACEi 29R-03

Their overlapping elements include: the description of FSA methods and their limitations, discussions on concurrency, delay categorization, the importance of source data validation (including schedules), the concepts of acceleration and mitigation as well as the criticality of establishing a cause and effect nexus from cotemporaneous documentation sources in pinpointing accountability for the delays. Both protocols strongly note that they are non-prescriptive guidance documents to be applied with common sense, thereby demonstrating how they can be harmonized to support robust delay analyses in international arbitration. Further commonalities between the protocols are explored in the section below.

Definition of Delay and Delay Categories

Both protocols concur that "delay" represents the variance between the planned and actual duration of an activity (i.e., "extended duration") or a sequence of activities (also known as "a path") remaining neutral regarding culpability. A delaying event, accordingly, constitutes a trigger for delay impacting an activity's execution, which may or may not influence the project's completion date.

Furthermore, the protocols align on the notion of "critical delay" as a "delay to the progress of any activity on the critical path that without acceleration or resequencing will cause the over project duration to be extended."⁷ Such critical delays frequently lead to escalated time-related costs (i.e. "delay damages") known as "Prolongation Costs" in the SCL D&D2 Protocol or "Extended Overhead Costs" in 29R-03.

The protocols also acknowledge multiple delay categories. Whereas SCL D&D2 classifies them by accountable party (e.g., Employer Delay, Contractor Delay, Concurrent Delay), 29R-03 frames them in terms of liability (e.g., Non-Excusable Delay, Excusable Delay, Concurrent Delay), yet fundamentally, both categorize delays according to their origins. Ultimately, ascertaining the quantum of delay damages recoverable by a contractor or assessable liquidated damages by an owner hinges on the fact-finder's ability to allocate delay days into these respective categories.

General Approach to Delay Analysis

A further key alignment lies in their overarching strategy for conducting delay analysis to ascribe responsibility and compute damages. Both endorse four principal stages: 1) Select a Delay Analysis Methodology, 2) Quantify Delay, 3) Identify Underlying Delay Causes, 4) Assign Responsibility. Each of these stages are elaborated below.

The initial stage entails selecting the delay analysis methodology that will be performed in determining the critical path in various periods of time and determining the amount of delay on the critical path in these periods as well as the aggregate project delay. Where the protocols modestly differ, 29R-03 concentrates exclusively on CPM-based techniques, whereas SCL D&D2 encompasses non-CPM alternatives. Nonetheless, both stress the prerequisite collection of adequate data to inform method selection (e.g., contemporaneous updates are essential for a Time Slice/Windows Analysis). They further concur that the contract's provisions on delay categorization (excusable/non-excusable or owner/contractor) and concurrency must be heeded.

Stage two advises validating data quality (e.g. schedule validation of actual dates, logic ties, etc.). Both provide general recommendations on the methodologies themselves and some caveats to consider. 29R-03, however expounds in greater depth regarding the minimum protocols necessary to perform a methodology as well as more advantages and drawbacks for each method. The SCL D&D2 Protocol has a total of five pages written on the methodologies while 29R-03 has over 55 pages written on the methodologies themselves. Concluding this stage, both insist on transparency to enable replication by counterparts or tribunals, decrying opaque "black box" analyses.

The third stage centers on causation. Both advocate thorough scrutiny of contemporaneous records, witness accounts, opposing expert reports, and testimonies from all parties to establish causes of critical path delays. Objectivity and impartiality are paramount, requiring evaluation of all evidence — even unfavorable to one's client — prior to causal conclusions.

The fourth stage involves assigning responsibility per the third stage's findings. SCL D&D2 implies determination by contract administrators, adjudicators, judges, or arbitrators, and not the testifying expert.⁸ 29R-03 however indicates as part of the quantification of delay events that the analyst may "determine responsibility or proceed based on assumed allocation of responsibility."⁹

FSA Methodologies

The protocols agree that there are different delay analysis methodologies with different purposes at the analyst's disposal. They also agree that some methods adopt either a "cause-based" approach or an "effect-based" approach.¹⁰ As explained by the SCL D&D2 Protocol:¹¹

Certain methods start with the identification and description of an event (a cause) and thereafter seek to establish its impact (the effect) [cause-based approach]. Other methods start with identifying the critical delay (an effect) and thereafter seek to establish what might have caused that delay [effect-based approach].

The protocols also agree that "delay analysis requires the identification of the critical path(s) to the completion date"[or another contractual milestone to which delay is being measured such as those tied to liquidated damages].¹² Lastly, the protocols agree that the critical path and delay impact may be determined prospectively, contemporaneously, or retrospectively contingent on the chosen technique.

Distinctions Between the Two Protocols

Depth of FSA Explanation

The primary disparity resides in the extent of elaboration on each FSA methodology. Also, 29R-03 delineates nine FSA methodologies while D&D2addresses six. The D&D2 Protocol spends approximately five pages examining these six methods, offering a concise paragraph per method, while 29R-03 spends a total of 55 pages on all nine methodologies or approximately eight pages per FSA method.

The accompanying figure illustrates the comparative detail levels. The left side of the figure lists the topics explained in 29R-03 (items A-M) for each of the nine FSA methods; the right contrasts SCL D&D2's coverage.

Figure 2: FSA Methodologies Level of Detail: 29R-03 vs. SCL D&D2

In 29R-03, the FSA metRhods are codified as Method Implementation Protocols (MIP) 3.1-3.9."The intent of the Method Implementation Protocols (MIP) is to describe each forensic schedule analysis method identified in the Taxonomy and to provide guidance in implementing these methods."¹³

Each of the nine MIP sections in 29R-03 contains: the description of the method, other common names of the method used in the industry, the manner in which the schedules must be validated to ensure integrity and accuracy before performing the chosen method (items A-D), guidelines and steps for implementing the method (items E and F), identification of the critical path, identifying concurrency/pacing, and how to quantify delay into its categories (items G-I), and caveats in choosing the method as well as limitations with the method itself (items L and M).

The right side of the figure summarizes the FSA methodologies covered by SCL D&D2 in the table found in the document.¹⁴ For each FSA method, SCL D&D2 dedicates a paragraph to explain the method and caveats to consider. For example, for the time slice analysis (comparable to "the windows analysis" in 29R-03), SCL D&D2 devotes the following paragraph to explaining the methodology:¹⁵

The time slice analysis method is the first of two 'windows' analysis methods. This method requires the analyst to verify (or develop) a reliable series of contemporaneously updated baseline programmes or revised contemporaneous programmes reflecting an accurate status of the works at various snapshots (being the time slices) throughout the course of the works. Through this process, the progress of the works is divided into time slices. The time slices are typically carried out at monthly intervals. The series of time slice programmes reveals the contemporaneous or actual critical path in each time slice period as the works progressed and the critical delay status at the end of each time slice, thus allowing the analyst to conclude the extent of actual critical delay incurred within each window. Thereafter, the analyst investigates the project records to determine what events might have caused the identified critical delay in each time slice period. For each time slice programme the analyst needs to verify that the historical components reflect the actual progress of the works and that its future sequences and durations for the works are reasonable, realistic and achievable and properly logically linked within the software.

Furthermore, the SCL D&D2 Protocol's section "Part B Guidance on Core Principles" also touches upon some of the elements in 29R-03 related to concurrent delay, float, acceleration, delay identification, and delay impact. In addition, both documents mainly agree regarding the application of these core principles.

Thus, while both discuss FSA methods, 29R-03 emphasizes their intricacies and execution, whereas SCL D&D2 provides overviews without in-depth implementation details.

FSA Methodologies and Naming Conventions

As shown in Figure 3 below, 29R-03 enumerates nine FSA methodologies while SCL D&D2 specifies six methodologies (noted in bold in the figure below).

Figure 3: FSA Methodologies and Naming Conventions

Each entry correlates 29R-03's naming with SCL D&D2's equivalent. For example, Item 2's "Static Windows" in 29R-03 equates to "As-Planned vs As-Built (APAB) Windows" in SCL D&D2. 29R-03 mitigates naming variances by listing common aliases.

Bracketed items denote variants of the six core methods. Both thus recognize the following methodologies:

• As-Planned vs. As-Built (APAB)
• Windows Analysis
• Impacted As-Planned
• Time Impact Analysis
• Collapsed As-Built (CAB)

The only FSA technique not explained in the SCL D&D2 Protocol is the half-step analysis (Item 4 in the figure above). The Retrospective Longest Path Analysis detailed in the SCL D&D2 Protocol mirrors the "As-Built Critical Path" addressed in 29R-03 throughout the individual MIP sections throughout the document and in Section 4.3.C: Critical Path and Float-Identifying the As-Built Critical Path. However, at the time of this publication, 29R-03 does not have a specific MIP addressing a Retrospective Longest Path Analysis/As-Built Critical Path, which may change in future revisions of the document.

Both protocols concur on definitions and limitations of shared methods; the variance lies in explanatory depth of both protocols.

Concurrent Delay Terminology

"Concurrent" implies simultaneity. Thus, concurrent delay denotes multiple delays occurring contemporaneously, though interpretations vary across methodologies, protocols, experts, and triers of fact. Hence, "the identification and quantification of concurrent delay is arguable the most contentious technical subject in forensic schedule analysis."¹⁶

'Literal' (29R-03) and 'True' (D&D2) Concurrent Delay

Literal concurrent delay mentioned by 29R-03 also occurs when delay is caused by multiple parties at the same time.¹⁷ This definition also aligns with SCL D&D2's definition of true concurrency, which is the occurrence of two or more delay events at the same time, one an Employer Risk Event, the other a Contractor Risk Event, and the effects of which are felt at the same time.¹⁸ True concurrent delay is infrequently encountered in delay analysis.¹⁹ Both protocols agree on this concept.

'Functional' (29R-03) and 'Sequential' Concurrent Delay

29R-03 adds a category of concurrent delay based on the "Functional Theory" where two delaying events, each to an opposing party, occurred within the same analysis time period but are not literally overlapping in time.²⁰ At the end of the analysis time period, the project completion date would be extended by both events. "The assumption made by the functional theory practitioner is that most delays have the potential of becoming critical, once float on the path on which they resides has been consumed."²¹

SCL D&D2 terms this sequential concurrency, more prevalent, delays arising at different times but effecting simultaneously.²²

Prospective v. Retrospective Analysis

The SCL D&D2 makes prospective analysis a core principle and strongly favors addressing delay in real time, or nearly so, when the parties have fresh first-hand knowledge of the delaying events. Still, SCL also affirms that the chosen approach must consider the unique conditions of the events and does not preclude retrospective evaluations when warranted. Even with its second edition, the SCL Protocol does not automatically overcome the risks that accompany settling a potential dispute prospectively based upon estimates for delays and cost impacts. SCL acknowledges prospective settlement risks but prefers early resolution if fact-based.

Conversely, 29R-03 is based solely on retrospective analysts which can still be applied on an active project. In the author's experienced, real-time windows analyses can aid change orders and resource management but still remain hindsight-oriented. A primary advantage of retrospective analysis is that modeled results can be calibrated to actual experiences on the job. Retrospective benefits include calibration to actual outcomes (e.g., validating prospective TIAs). It mitigates hindsight bias by adopting contemporaneous perspectives.

Pacing

SCL D&D2 views pacing as delay mitigation, advising employer notification if intended, without elaboration. Conversely, 29R-03 dedicates a section to pacing and provides some guidance in its use relative to those delay analysis methodologies where it applies.²³

How the Protocols Empower Party-Appointed Experts

In the author's extensive involvement in international arbitrations, where intricate delay and disruption claims frequently arise, party-appointed delay experts are pivotal in substantiating or rebutting such claims on behalf of our appointing parties. The integrated application of the SCL D&D2 and 29R-03 significantly bolsters our capacity to deliver analyses that are not only robust and credible but also highly defensible under scrutiny. To illustrate the synergy between the two protocols in action, consider the following example from the author's experience in preparing an expert report on a complex delay claim for presentation to an international arbitration tribunal.

Guidance on Methodology Selection

Drawing from SCL D&D2, an expert can justify his or her methodological choices by tailoring them to the project's unique context, including the extent of available records or the analysis's timing — whether prospective or retrospective. Complementing this, 29R-03's comprehensive taxonomy equips an expert to pinpoint and execute the optimal technique with precise technical depth. The SCL D&D2can be used to assess the project's records, schedule updates, and the nature of the dispute (e.g., prospective vs. retrospective analysis) while 29R-03 will identify the most suitable methodology based on the available data and the analysis's objectives.

For example, on a multifaceted project plagued by patchy documentation, an expert might lean on SCL D&D2 to advocate for a retrospective method such as As-Built vs. As-Planned, then turn to 29R-03 for the granular procedural steps to ensure its accurate execution.

Ensuring Robust Analysis

SCL D&D2's focus on a clear critical path analysis and the primacy of contemporaneous records, which experts should prioritize to uphold the integrity and believability of their work product. Meanwhile, 29R-03 furnishes the expert with the tools for precise delay quantification, such as modeling the impact of delay effects on the critical path or dissecting concurrent delays. Therefore, an expert would apply 29R-03's step-by-step process to conduct the technical analysis, ensuring accuracy and consistency while adhering to SCL D&D2's guidance on using contemporaneous evidence and clearly documenting the critical path.

Defensibility in Arbitration

Arbitration tribunals value analyses that are clear, logical, and supported by industry standards. SCL D&D2's emphasis on fairness and clarity ensures the expert's findings are presented in a way that is accessible to arbitrators. 29R-03's standardized methodologies lend technical credibility, reducing the risk of challenges to the expert's approach. For example, an expert can present an APAB in Windows (per 29R-03) while referencing SCL D&D2's principles to explain why this method was chosen, creating a persuasive and defensible case.

Furthermore, international arbitrations usually entail complex delay analysis claims. Complex claims often involve concurrent delays, acceleration, and multiple critical and "near" critical paths. SCL D&D2 provides guidance on addressing these issues holistically, while 29R-03 offers specific techniques to analyze them.

Conclusion

In my experience as a delay expert engaged in international construction arbitrations, the engagement of party-appointed delay specialists is indispensable when navigating intricate delay and disruption claims, enabling parties to substantiate their positions and construct formidable defenses. Both the SCL D&D2 Protocol and AACEI's 29R-03 have been recognized by arbitration tribunals as invaluable instruments in this regard. As elaborated in this paper, these frameworks are far from incompatible; rather, they are synergistic, and when applied thoughtfully, they empower independent experts to fulfill our duties to the tribunal with rigor and integrity.

Above all, my professional journey has underscored that adaptability and pragmatic judgement are key to advancing delay-related claims effectively. Arbitral panels invariably expect experts to uphold objectivity, adapt our analyses to the project's specific realities, collaborate constructively with the opposing expert to isolate and resolve contested issues, and ultimately assist the tribunal in reaching well-founded determinations. By leveraging both the SCL D&D2 and 29R-03 judiciously, experts can derive impartial, robust conclusions that tribunals can depend upon in rendering their awards.

References

1. Society of Construction Law (UK). Delay and Disruption Protocol, 2nd ed. Leicestershire, UK: Society of Construction Law, 2017. https://www.scl.org.uk/resources/guidelines/delay-disruption-protocol-2nd-edition.
2. AACE International (2011) Recommended Practice No. 29R-03: Forensic Schedule Analysis. Morgantown, WV: AACE International. https://web.aacei.org/docs/default-source/rps/29r-03.pdf

Footnotes

1. Note: the terminology "schedules" and "programmes" are identical in this publication, "schedules" is used more predominately used in North America while "programmes" is used in the United Kingdom, Europe, Australia, Asia and the Middle East.

2. SCL Delay and Disruption Protocol 2^nd Edition, page 1

3. Ibid.

4.A ACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 9

5. Ibid.

6. Ibid.

7. SCL Delay and Disruption Protocol 2^nd Edition, page 62

8. Ibid. page 43

9. AACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 37

10. Ibid. page 34

11. SCL Delay and Disruption Protocol 2^nd Edition, page 33

12. Ibid. page 33

13. AACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 38

14. SCL Delay and Disruption Protocol 2^nd Edition, pages 34-35

15. Ibid. page 36

16. AACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 101

17. Ibid., page 104

18. Society of Construction Law Delay and Disruption Protocol (2nd ed, February 2017) Section 10 et al.

19. Ibid. Para. 10.3

20. AACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 104

21. Ibid.

22. Society of Construction Law Delay and Disruption Protocol (2nd ed, February 2017), Para. 10.4

23. AACE International RP 29R-03 Forensic Schedule Analysis Rev April 25,2011, page 111

This article was first published by SCL International [https://www.sclinternational.org/papers]