How to challenge an opposing expert report: the counter-report
If the opposing report contains errors, the counter-report exposes them technically. This is how an expert opinion is rebutted before the judge.
The counter-report reviews the methodology, data and regulations of the opposing report.
When the opposing expert report works against you
In many proceedings, the opposing party files its own expert report. If that report contains errors, omissions or forced conclusions, leaving it unanswered can cost the case. The technical tool to rebut it is the expert counter-report.
What a counter-report is
A counter-report is an expert opinion that critically reviews the opposing party's report. It does not merely disagree: it analyses the methodology, checks the data and sets out, in technical terms, where it fails, so the judge can weigh both with proper criteria.
A good counter-report answers three questions:
- Is the methodology sound? Were the right tests carried out, or was the conclusion drawn from a simple visual inspection?
- Do the data support the conclusion? Are there logical leaps, missing measurements or undated photographs?
- Is the correct regulation applied? A regulatory error (CTE, LOE, EHE) can invalidate the whole argument.
Common flaws in party reports
- Conclusions without supporting tests.
- Confused causes (for example, attributing to condensation what is infiltration).
- Cost assessments without a breakdown or measurement criteria.
- Lack of traceability: it is impossible to reconstruct how the conclusion was reached.
- Overreach: the expert opines outside their specialty.
Detecting and documenting these points is what turns disagreement into evidence.
The ratification moment
The counter-report is completed at the hearing, when both experts appear. Rigorous preparation makes it possible to put precise technical questions to the opposing expert that expose the weaknesses of their report before the judge. This oral defence stage is as important as the written document.
A full counter-report is not always needed
Sometimes a technical review is enough to help the lawyer prepare cross-examination; other times, a full alternative report is warranted. The decision depends on the strength of the opposing report and what is at stake. We assess it case by case within our counter-report service and our collaboration with lawyers.
Facing an expert report you are not convinced by? Send it to us and we will tell you whether it can be rebutted, and how.
