Antitrust law
Role of economic expert testimony in merger trials and methods to present complex analyses clearly to judges.
In merger litigation, economic experts translate market dynamics, price effects, and competitive harm into accessible evidence, guiding judges through intricate analyses with clarity, balance, and strategic storytelling that aligns with legal standards.
Published by
Wayne Bailey
August 12, 2025 - 3 min Read
Economic expert testimony in merger trials functions as a bridge between sophisticated quantitative models and the courtroom realities judges face. Experts must translate complex econometrics, market definitions, and hypothetical constructs into a narrative that is legally coherent and persuasive. They begin by framing the core question—will the merger lessen competition?—in terms that align with antitrust law, policy goals, and the record before the court. Calibration matters: selecting appropriate market boundaries, data sources, and time horizons so the analysis remains credible under cross-examination. The strength of such testimony lies not only in precision but in how clearly the underlying logic can be traced step by step by non-economist decision makers.
To ensure accessibility, experts should organize testimony around a simple storyline: define the market, identify competitive constraints, measure effects, and assess remedies if harm is found. This structure helps judges follow the reasoning without getting lost in algebra or unrelated theory. Visual aids, such as clean charts and concise tables, can illuminate key points without oversimplifying. When addressing unilateral effects, the expert can explain how a merged firm could raise prices or reduce output, linking these projections to real-world incentives observed in the data. In merger-forward analyses, sensitivity tests demonstrate robustness and reveal how conclusions shift under alternative assumptions.
Anticipating critique reinforces credibility and preserves persuasive impact.
A core requirement is consistency between the economic model and the legal issue at stake. Experts must articulate the model's assumptions, the data's limitations, and the inferential steps that connect numbers to conclusions. This involves a careful discussion of identification strategies, potential biases, and the boundary conditions of the results. When presenting market shares, concentration measures, or welfare calculations, the analyst should tie each figure to the specific decision faced by the court. Clarity here reduces disputes about methodology and helps the judge grasp not just what happened, but why it matters within antitrust doctrine.
Cross-examination can threaten the perceived integrity of the analysis if foundational elements are not transparent. To withstand scrutiny, the expert should preemptively disclose data sources, code, and model specifications, while offering an accessible executive summary for the bench. Demonstrating reproducibility—receiving permission to show how results would vary under alternative data selections—builds trust. Moreover, the expert can anticipate common objections, such as endogenous data concerns or sample biases, and explain how these were mitigated or why they do not drive the main conclusions. The goal is to remain rigorous without becoming unreadable.
Remedies analysis requires transparent, scenario-based evaluation.
In communication, simplicity is an asset, not a betrayal of rigor. Presenters should avoid jargon-heavy explanations that alienate judges who may not be statisticians. Instead, they should translate technical findings into practical implications: what the merger could do to prices, product quality, and consumer choice. The expert can illustrate with concrete scenarios, comparisons to past mergers, and intuitive analogies that illuminate the mechanisms at play. The emphasis is on establishing a plausible narrative that aligns with legal standards for harm and with the record of economic evidence introduced by both sides. The more the audience can see the causal chain, the stronger the testimony becomes.
In practice, delineating the remedies or structural constraints also matters. If the court contemplates a fix, the expert should quantify the expected impact of divestitures, behavioral restrictions, or other interventions. This involves modeling post-merger behavior under proposed remedies and demonstrating whether competitive constraints would re-emerge. By presenting a before-and-after comparison, the economist can show that the remedy is both sufficient and proportionate. Clear articulation of these impacts helps courts decide not only whether harm exists, but whether a proposed remedy would restore competition to an acceptable level, minimizing distortions to consumer welfare.
Credibility and humility strengthen the jurist’s trust in analysis.
Beyond numerical results, the presentation must address institutional context. Antitrust cases hinge on public interest, so economists should connect their findings to policy objectives like consumer welfare, innovation, and market dynamic resilience. Explaining how the merger could affect entry barriers, innovation incentives, and long-run competition can make the analysis resonate with judges who weigh broader societal consequences. When discussing welfare effects, the expert should distinguish between short-run and long-run implications, making explicit any trade-offs. A well-argued testimony integrates empirical findings with normative considerations in a way that remains faithful to the evidence.
Ethical considerations also shape credible testimony. Economists must avoid overstating certainty, acknowledging uncertainty where it exists and clarifying the limits of extrapolation. They should disclose any industry-specific quirks, data gaps, or external factors that could alter outcomes. By maintaining professional humility and precision, the expert preserves trust with the court and reduces the risk of appeals grounded in methodological disputes. In this spirit, the testimony becomes not merely a set of numbers but a disciplined, responsible contribution to the legal process.
Relating results to real-world effects aids judicial comprehension.
The use of simulations and counterfactuals often clarifies what the merger might change. Economists can compare scenarios with and without the transaction, showing how prices, output, and margins would diverge under each condition. Presenting these counterfactuals in a structured way helps judges evaluate causal claims without needing to navigate arcane technicalities. For measures of market power, such as pass-through rates or elasticity estimates, the expert should explain the intuition behind the results and why they are relevant to the case at hand. The effective use of scenario planning supports robust decision-making by the court.
Judges benefit from a coherent, bias-aware narrative that ties every model choice to the central inquiry. Explaining why a particular market definition was adopted, why a control group is valid, and how outliers were treated makes the analysis relatable. The expert should also clarify the role of ancillary analyses—such as sensitivity to data period or competitor responses—as essential context rather than optional extras. When appropriate, linking the numeric results to real-world consumer experiences helps the bench grasp the practical significance of the projected competitive effects.
The role of economic expert testimony extends to negotiating with opposing counsel as well as informing the judge. A collaborative posture—where the economist explains, listens, and adjusts where necessary—can defuse adversarial tensions and yield a more accurate portrayal of economic dynamics. Clear, precise briefing documents, frequent check-ins with the bench, and the avoidance of sensational claims all contribute to a more constructive process. In high-stakes merger disputes, the ability to align technical rigor with courtroom practicality often determines whether the evidence is persuasive or merely illustrative.
Ultimately, effective economic testimony helps courts uphold competitive markets without stifling legitimate business activity. By delivering rigorous, accessible analyses that map directly to legal standards, economists support outcomes rooted in reality rather than rhetoric. The aim is to empower judges to evaluate complex market interactions with confidence, recognize when remedies are warranted, and appreciate the durability of competitive dynamics over time. As mergers continue to reshape industries, the responsibility to present clear, honest, and well-supported conclusions remains a defining feature of responsible antitrust practice.