The Court of Arbitration for Sport (CAS), based in Lausanne, Switzerland, serves as the primary international tribunal for resolving disputes over eligibility, disciplinary rulings, contract disagreements, and anti-doping accusations. CAS proceedings are governed by the CAS Code of Sports-related Arbitration, which sets out the framework for submissions, hearings, provisional measures, and evidentiary presentation.
CAS is not a national court. It is an international arbitral tribunal. That distinction matters when it comes to how evidence is gathered, presented, and assessed. Athletes unfamiliar with the international sports arbitration model can find themselves at a serious disadvantage before proceedings even begin.
At Global Sports Advocates, our international sports law attorneys have represented athletes from around the world across nearly every sport. We understand how CAS panels assess evidence, and we know what it takes to build a persuasive case that protects your career, your reputation, and your right to compete.
Table of Contents
The Standard of Proof in CAS Proceedings
One of the most important concepts in any CAS proceeding is the standard of proof—the threshold that must be met before a panel accepts a fact as established. The applicable standard varies depending on the nature of the dispute and which party bears the burden.
Comfortable Satisfaction
In disciplinary cases, including most anti-doping matters, the body bringing the charge bears the initial burden of establishing a violation. CAS panels commonly apply the standard of comfortable satisfaction. This standard lies between the civil standard of balance of probabilities and the criminal standard of beyond a reasonable doubt.
The consequences of a disciplinary finding—suspensions, disqualification of results, loss of medals, reputational harm—are severe and career-altering. CAS jurisprudence recognizes that such consequences justify a higher evidentiary threshold than ordinary civil disputes, even though the proceedings are not criminal in nature.
Burden Shifting in Anti-Doping Cases
In anti-doping matters, once a violation is established, the burden shifts to the athlete. If the athlete seeks to reduce or eliminate a sanction by proving No Fault or Negligence or No Significant Fault or Negligence, the standard applied is typically the balance of probabilities—meaning the athlete must show that their explanation is more likely than not.
Strategically, this burden-shifting framework makes early evidence preservation critical. Documentation, supplement analysis, medical records, expert opinions, and consistent testimony often determine whether a sanction is reduced.
Contract and Eligibility Disputes
In contractual or eligibility disputes, the burden is generally a balance of probabilities. Each party must prove the facts that support its position. CAS panels examine all submissions collectively and determine which version of events is better supported by the evidence.
Provisional Measures
Not every CAS dispute can wait for a full hearing. When a sanction threatens to sideline an athlete during an active season or prevent participation in a major event, time is of the essence. CAS Rules allow a party to request provisional or interim relief asking a panel to suspend a sanction or preserve the status quo while the case on the merits is pending.
To succeed on a request for provisional measures, an athlete must demonstrate three things:
- The relief is necessary to protect the applicant from irreparable harm.
- The claim has a likelihood of success on the merits.
- The balance of interests favors granting the measure
This is a high bar. Panels do not routinely grant provisional relief, and a poorly prepared request can undermine the credibility of the broader case.
Types of Evidence Accepted in CAS Proceedings
CAS panels may admit any evidence they deem relevant. Unlike traditional courts, CAS is not bound by rigid evidentiary codes. However, panels still assess weight, reliability, and credibility carefully.
Documentary Evidence
Contracts, regulations, correspondence, federation decisions, laboratory documentation, medical records, and digital communications often form the backbone of a CAS case.
Witness Statements
CAS commonly relies on written witness statements submitted before the hearing. These statements can stand as direct testimony, with live questioning limited to cross-examination and re-direct.
Expert Evidence
In anti-doping cases, pharmacologists, toxicologists, laboratory directors, and scientific experts frequently testify. In eligibility or governance disputes, federation experts may be called. CAS panels may consider both party-appointed experts and, in rare instances, tribunal-appointed experts.
Electronic Evidence
Emails, text messages, GPS data, social media posts, and digital logs increasingly can play a central role in disputes. Panels assess authentication, context, and completeness.
Physical Evidence
Supplements, equipment, or preserved samples may be relevant in specific cases. The integrity of such evidence, including the chain of custody, is often decisive.
Building a Persuasive Narrative
CAS panels evaluate evidence in its totality. No single piece of evidence automatically determines the outcome.
The most persuasive cases:
- Present a coherent, chronological narrative
- Align documentary, scientific, and testimonial evidence
- Anticipate credibility challenges
- Address weaknesses directly
- Avoid overreaching
At Global Sports Advocates, we have successfully represented athletes in some of the most high-profile CAS proceedings in the world. We know how to build cases that meet the required standard of proof, how to present credible and compelling testimony, and how to protect athletes’ careers at the highest level of international sport.
If you are facing a CAS appeal or disciplinary proceeding, we encourage you to contact our office to discuss how experienced guidance can make the difference between a career-altering sanction and a successful defense.
