Mega projects, mixed disputes: the hybrid ADR playbook

Complex cross-border construction projects rarely present a single type of dispute. Technical disagreements, valuation claims, delay and disruption, and multi-party liability questions can all surface on the same project, often at different stages.

The most effective dispute resolution strategies do not rely on a single mechanism. Instead, they deploy some combination of dispute boards, arbitration and/or mediation at different points in a project's lifecycle, each serving a distinct function: dispute boards for project governance and dispute avoidance, arbitration to clarify risk and deliver enforceable outcomes, and mediation to find commercially workable settlements.

Getting this right takes more than a well-drafted multi-tier dispute resolution clause. It requires strategic choices about which mechanisms to use, and when.

Below we outline practical considerations, common pitfalls and best practices for each of these three pillars of hybrid ADR in mega projects.

Catch it early: expert determination and dispute boards

Complex construction contracts will often include an expert determination or dispute board procedure as an optional or mandatory step before arbitration, which is intended to be short and cost-effective. These mechanisms are rarely found together in the same contract. They are alternative approaches, each suited to different disputes and different strategic goals.

In most jurisdictions, including the UK, Hong Kong SAR and Singapore, failing to comply with a multi-tier dispute resolution clause is treated as a question of admissibility, not jurisdiction. In practice, this means skipping a pre-arbitration step does not deprive the arbitral tribunal of jurisdiction. Instead, the tribunal can decide whether to continue, dismiss or stay the arbitration and send the parties back to complete that step first.

This makes careful drafting of mandatory pre-conditions more important: vague or aspirational language risks being read as directory rather than mandatory, leaving the pre-arbitral mechanism with no real procedural teeth.

Expert determination is typically used where the parties want to carve out a narrow set of issues from immediate referral to arbitration. These are often technical or valuation disputes that can be as specific as owner-caused delays or breach of a latent defects warranty, or they can expand to encompass much wider categories of disputes.

A sole expert with relevant specialist expertise usually runs the process on a shorter timescale than dispute board proceedings, making it quick and cost-effective.

Under some contracts, expert determination can be inquisitorial in nature rather than based on natural justice, where the expert determiner has the flexibility to investigate independently, including reviewing documents and visiting a party's offices without the other side present. That flexibility, combined with the ability to appoint an expert with precisely the right technical and legal background, is what makes expert determination well suited to discrete issues that can be cleanly separated from more complex claims.

Dispute boards are more commonly adopted where the parties intend for all disputes to pass through an additional procedural layer before arbitration. Standing dispute boards, in particular, combine project familiarity with contemporaneous knowledge of what is happening on site, giving them a significant edge over ad hoc appointments.

How a case is presented to a dispute board should be a deliberate strategic choice. There are two broad approaches: a streamlined, lower-cost submission designed to resolve the issue quickly while saving full case preparation for any subsequent arbitration; or a comprehensive, arbitration-standard submission – effectively a mini-arbitration – with detailed submissions, witness statements and expert reports, aimed at putting maximum pressure on the counterparty to settle or face an unfavourable decision.

The choice depends on many factors, including the nature and value of the dispute as well as the players involved. For example, the streamlined approach may suit discrete, lower-value issues where speed is the priority, and the parties are willing to engage in the procedure. For more consequential claims involving commercially-minded parties and a sufficient risk appetite on the claimant’s part, the mini-arbitration approach can demonstrate the strength of the referring party's case and sharply increase the pressure to settle.

Depending on the contract, expert determinations and dispute board decisions may be binding but not final, with arbitration required for a final legally enforceable resolution. Their practical value therefore depends heavily on genuine cultural and commercial buy-in.

Where, for instance, the works are already complete and both parties want to close out outstanding issues, redeploy resources and move on, there is a natural incentive on both sides to engage constructively. The alternative is a longer, costlier arbitration with no guaranteed better outcome for either party. The flip side is real risk: the time and cost invested in a dispute board submission, particularly on a mini-arbitration approach, may need to be spent again in a full arbitration if the dispute is not resolved before then.

The latest survey by King’s College London on dispute boards (132-pages / 9.8MB PDF) shows that binding decisions are complied with most of the time. Even where a dispute board cannot stop every dispute from reaching arbitration, it still serves a valuable project governance function: rather than a mere gateway to arbitration, it helps the project team prepare for any subsequent proceedings. Both a dispute board decision and an expert determination can also give the tribunal a foundation for understanding complex technical issues.

Arbitration at scale: taming cost and complexity

For cross-border mega projects, international arbitration remains the backbone of dispute resolution. According to the latest survey from Queen Mary University of London (QMUL) (46 pages / 2.1 MB PDF), an overwhelming majority (87%) of respondents still choose international arbitration to resolve cross-border disputes, whether alongside ADR (48%), or as a standalone mechanism (39%).

For end-users, the priorities are efficiency, finality and enforceability and the outcomes must also satisfy internal governance and audit requirements, particularly where state-owned entities or public bodies are involved. Meeting those goals in mega-project disputes takes deliberate, proportionate case management, and the major arbitral institutions have responded with an increasingly sophisticated toolkit.

Arbitration is the final stage of the multi-tiered dispute resolution procedure. But a final award can take a long time to be finalised and issued. This is not ideal for a party that needs immediate relief, for example to stop a counterparty disposing of assets or breaching the contract while the dispute is being resolved.

Emergency arbitration can fill that gap. Under the SIAC Rules 2025, a party can apply for emergency interim relief, and even for ex parte protective preliminary orders to stop a counterparty frustrating that relief, before filing a formal notice of arbitration.

The emergency arbitrator must issue an order or award within 14 days – 24 hours for a protective preliminary order application – making the procedure well-suited to time-sensitive situations such as resisting bond calls, preventing the dissipation of assets or preserving the status quo on a live project. The International Chamber of Commerce (ICC) has similarly expanded its emergency arbitration provisions under its 2026 Rules.

However, in some jurisdictions, enforceability of an emergency arbitrator's interim award is uncertain. The Singapore High Court recently refused to enforce a CIETAC China-seated award because PRC law does not recognise arbitrators' powers to issue interim measures. That risk is worth weighing up before initiating the process.

Coordination and consolidation mechanisms have also become increasingly important where disputes arise across multiple tiers of the contractual chain. Energy and infrastructure projects, for example, typically generate disputes involving multiple contracts with the same parties, multiple parties to the same contract, and multiple contracts with multiple parties on the same project.

Major institutional rules now allow joinder of additional parties, consolidation of related arbitrations and, importantly, coordination of parallel proceedings before the same tribunal. Supply chain dynamics add a further layer of complexity: in multi-tier contract structures, information shared during arbitration has the potential to flow both upstream and downstream, so parties should be alive to the strategic consequences of disclosure, particularly where liability exposure spans several tiers of the contractual chain.

Coordinated proceedings let parties run related arbitrations on aligned timetables while keeping each case separate, which is especially useful for managing back-to-back claims across the main contract and subcontract levels without formal consolidation. However, achieving coordination requires careful planning, including ensuring that the same tribunal is constituted across the related proceedings, which may require specific drafting in the underlying contracts.

Early determination and preliminary rulings allow tribunals to dispose of claims or defences at an early stage, or to resolve threshold issues that could decide the outcome. For mega-project disputes, these tools – which are amongst the most effective mechanisms for enhancing efficiency according to the latest Queen Mary Survey – have obvious strategic value: they can narrow the scope of the arbitration, resolve jurisdictional or admissibility challenges arising from multi-tier clauses, and create a pathway to settlement by clarifying the parties’ positions on key issues before the full cost of a hearing is incurred.

Proportionate case management remains essential across all of these mechanisms. In mega project arbitrations, the volume of potentially relevant documents can be overwhelming, and limiting production to what is genuinely necessary — where possible adopting civil law-style rules that restrict broad disclosure requests — can significantly cut cost and delay. Expert evidence needs equally careful handling: joint expert reports directed by the tribunal, early agreement on the scope of expert issues, and narrowing disagreement through expert meetings before the hearing all help the tribunal focus on what actually matters. Active case management by the tribunal is now the procedural anchor point.

Mediation grows up: from settlement to deal-making opportunity

Construction disputes were once seen as too complex for mediation, but that perception has shifted. Mediation is now valued not only as a settlement mechanism, but as a forum for creative, commercially driven problem-solving.

In complex projects, a skilled mediator can help parties move past entrenched legal positions and explore solutions unavailable in arbitration, such as restructuring commercial arrangements, preserving business relationships, offering future work in exchange for a reduced claim, or reviving terminated agreements. That makes mediator selection important: the mediator should combine facilitative skill with sufficient industry and commercial understanding to identify solutions beyond the parties' stated positions. In cross-border disputes, co-mediation, with each side nominating a mediator, may help bridge cultural and procedural differences.

Mediation is often most effective when earlier proceedings have clarified the issues and the parties' respective exposure, making a negotiated outcome preferable to the cost and uncertainty of a final hearing. Timing and context are therefore critical, particularly in public-private partnerships where parties may be involved in several projects and preserving the commercial relationship can be as important as resolving the immediate dispute. If mediation begins too early, the parties may lack the information needed to negotiate meaningfully; if it begins too late, their positions may have hardened. Identifying the right window requires continuing strategic assessment. Even if no immediate settlement is reached, a well-managed process can preserve the prospect of renewed talks and lead to agreement later.

Institutional mediation is gaining traction compared to ad hoc mediation because established institutions provide credibility, accountability and confidentiality protections at limited additional cost. This procedural legitimacy may be decisive where governance, compliance or internal approval requirements apply, especially on projects involving state-owned entities or public-private partnerships.

Mediation is also becoming a more attractive component of the dispute-resolution toolkit for mega projects because settlement outcomes are now capable of cross-border enforcement through the United Nations Convention on International Settlement Agreements Resulting from Mediation, commonly known as the Singapore Convention on Mediation.

This convention establishes a harmonised framework for the enforcement of international commercial settlement agreements reached through mediation in much the same way that the New York Convention supports the enforcement of arbitral awards. As of 21 September 2026, the convention has attracted 60 signatories and 24 contracting parties, demonstrating growing international acceptance of mediation as a credible mechanism for resolving complex cross-border disputes.

Making hybrid ADR work: strategy, not sequence

There is rarely a single, best dispute resolution mechanism for a mega project. Expert determination and dispute board procedures support project governance and early intervention; arbitration supplies enforceability and finality; mediation can unlock outcomes beyond a tribunal's remedial powers. The three should be viewed as complementary tools to be deployed at the stage where each adds the most value. Their success ultimately comes down to the team knowing how to move strategically between them as a dispute, and the project, evolves.

This analysis draws on themes discussed during the SIAC and Pinsent Masons panel "The Hybrid ADR Playbook for Mega Projects: What Works, What Fails, and Why", held during Singapore Convention Week 2026.