Expert Evidence in Sports Arbitration: Instructing Experts at the CAS

Summary

Expert evidence is used in a minority of sports appeals, but where it is used it often decides the outcome. In October 2026 we read all 536 awards on the Court of Arbitration for Sport's recent decisions page. Most are appeals decided in 2023, 2024 and 2025. We looked at when experts are used, who they are, who calls them and what panels make of their evidence. This paper sets out what we found and turns it into practical guidance for legal teams handling a CAS appeal, or a federation case that may reach the CAS.

Five findings stand out.

• About one award in four (125 of 536, 23%) records expert evidence: a report, an opinion or oral testimony.
• Doping is where experts matter most. 61 of 118 doping awards (52%) involve expert evidence. The figure for football transfer and contract cases is 14%.
• Science dominates. Anti-doping scientists, toxicologists and pharmacologists account for 46% of the 129 expert appearances we could identify. Lawyers giving evidence on Swiss and other national law come next (14%), then medicine and sport science (12%).
• Experts are rarely heard alone. In 28 of the 65 awards that name their experts, the panel heard two or more. One award heard nine.
• The pool is small. The most frequently heard expert appears in five awards in our sample, and nine others in three or four. Conflicts, independence and availability need checking from day one.

The practical lesson runs through every section of the paper. At the CAS, what an expert can achieve is largely fixed by the appeal brief. By the time it is filed, the expert must be found, cleared of conflicts, briefed and close to a concluded view.