Introduction

Delay analysis for disputes is often treated as a technical exercise driven by scheduling software, industry guidelines, and recognized methods. In practice, delay disputes are rarely decided by data alone. They often turn on judgment — how experts interpret project records, choose an approach, and apply scheduling principles to what occurred on site.

This is why delay experts can study the same project records and reach different conclusions. That does not necessarily mean one expert is wrong or biased. It reflects that delay analysis is not a mechanical exercise.

Understanding why experts disagree, and how to manage those differences, helps produce reliable evidence to assist tribunals or courts.

The Expert’s Primary Duty

In international arbitration and court proceedings, an expert’s duty is to assist the decision-maker, whether the tribunal or court. The expert’s role is to help the decision-maker:

• Understand what was originally planned
• Understand what actually happened
• Understand why the delays occurred
• Reach a fair and reasonable conclusion based on the factual evidence

Courts have emphasized that experts assist the tribunal and should not act as advocates for the parties. In White Construction (Pty) Ltd v PBS Holdings (Pty) Ltd [2019], the court criticized the competing delay analyses as “complex and impenetrable.” Instead of accepting either expert’s analysis completely, the court adopted a simpler, more practical approach based on the factual evidence and common-sense approach.

The Myth of the “Correct” Delay Analysis

One of the biggest problems in delay disputes is the belief that there is always one “correct” delay methodology. In reality, methodology is only a tool. It is not the final answer. Delay methodology cannot:

• Fill every gap in project records
• Remove the need for professional judgment
• Automatically prove causation
• Replace an understanding of how the project was actually built

Structured methodologies are important because they provide consistency and transparency. However, methodology alone does not make an analysis reliable. The most convincing expert evidence explains why a particular approach was chosen and how it reflects the facts of the project.

In Walter Lilly & Company Ltd v Mackay [2012], the court placed significant importance on the factual history of the project and the actual causes of delay rather than relying on theoretical programming analysis. The case reinforced the principle that methodology should support the facts, not replace them.

What Tribunals or Courts Actually Care About

In practice, tribunals or courts often focus on considerations such as:

• Whether the analysis reflects the actual project records
• Whether the conclusions make sense when compared with the project history
• Whether the expert’s reasoning is clear and logical
• Whether the expert appears independent and objective
• Whether the analysis can be explained in simple terms

Complex modelling may help support an analysis, but tribunals and courts usually value clarity, independence, and practical judgment more than technical complexity. If an expert report becomes too complicated, too theoretical, too technical, or disconnected from what happened on site, it stops being useful.

Why Experts So Often Disagree

Even when experts review the same records, they often reach different conclusions. These disagreements usually happen for several reasons.

Different Preferred Method of Delay Analysis

Some experts strongly prefer one method of delay analysis and apply it in every case, even when the project records or dispute circumstances may not support it.

Different Interpretations of Records

Project records are rarely perfect. Programmes, progress updates, site diaries, and correspondence may be incomplete, inconsistent, or prepared after the events occurred. Experts often interpret these records differently.

Over Reliance on Software Outputs

Software-driven critical paths are sometimes treated as the final answer, even when they do not match the reality of how the project was managed on site.

Different Instructions and Assumptions

Experts are often asked to analyze different issues or work on different factual assumptions. Sometimes the disagreement exists because the experts are effectively answering different questions.

Large Volumes of Digital Data

Modern projects generate huge amounts of information, including schedules, emails, progress photographs, timelapse videos, daily reports, and design records. More data does not always create more clarity. In many cases, it creates more room for different interpretations.

Courts and tribunals have often expressed frustration when delay analyses become overly complicated or difficult to understand. In some cases, tribunals have preferred a more practical and common-sense approach instead of fully accepting either expert’s position.

• In Walter Lilly & Company Ltd v Mackay [2012], as mentioned above, the court focused heavily on the factual evidence and practical realities of the project rather than relying only on theoretical delay modelling.
• In Saga Cruises BDF Ltd v Fincantieri SpA [2016], the court highlighted the importance of considering the actual progress of the works and not relying blindly on programming analysis alone.

When Disagreement Becomes a Problem

Disagreement between experts is normal. It only becomes a problem when experts become too rigid or overly defensive about their methodology.

Problems can arise when experts ignore alternative views, try to force imperfect records into a preferred analysis, focus more on defending methodology than understanding the project facts, or become unwilling to accept reasonable limitations in their analysis.

Tribunals and courts are generally less concerned about the existence of disagreement itself. What matters more is whether the disagreement is approached fairly, reasonably, and transparently.

Practical Guidance for Delay Experts

To improve the quality of expert evidence and better assist tribunals or courts, experts should consider the following practical points.

Discuss Methodology Early

Where possible, experts should meet early in the process to narrow methodological differences. Even partial agreement on basic principles can reduce unnecessary disputes later.

Choose the Method That Fits the Case

Methodology should be selected based on:

• The contract requirements
• The purpose of the analysis
• The quality and availability of records
• The size and complexity of the dispute

There is no single methodology that works for every case.

Be Flexible

Industry guidelines should guide the analysis, not control it completely. Experts should adapt their approach to the available evidence rather than forcing the evidence to fit a preferred method.

Keep the Analysis Simple

If a delay analysis cannot be explained clearly and simply, it is probably too complicated. Experts should always consider whether someone unfamiliar with the project can still understand the conclusions.

Avoid False Precision

Delay analysis often involves incomplete information and retrospective judgment. Experts should avoid presenting conclusions with unrealistic levels of precision where the evidence does not support it.

Recognize Alternative Views

Good experts acknowledge that more than one interpretation may exist. Addressing alternative views openly usually strengthens credibility rather than weakening it.

Conclusion

Disagreement between delay experts is not a weakness in the discipline. It is a natural result of applying professional judgment to complicated projects and imperfect records.

Tribunals and courts do not expect experts to agree on everything. 

The best delay experts understand that methodology alone does not persuade tribunals or courts. Their real value comes from applying sound judgment, understanding the project facts, and explaining the story clearly, fairly, and independently.

Early discussions between experts can also help reduce unnecessary disagreement. In many cases, agreeing at an early stage on certain matters such as the key documents to be relied upon, the baseline schedule, the methodology, the actual critical path can significantly narrow the issues in dispute and better assist the tribunal or court.

The views and opinions expressed in this article are those of the authors.