The article discusses the problem of the use in litigation of statistical sampling. Sample-based research is increasingly used in cases as diverse as products liability, antitrust, intellectual property, and criminal law, among others. Sample-based research provides objective evidence upon which decisions, damages and liability may rest. Despite its importance, however, statistical evidence is often misused and misunderstood by attorneys who may be unfamiliar with the underlying form of analysis. The paper explores common errors when using litigative samples, comments upon best practices for the use in law of sample-based research, and demonstrates the importance of sound statistical sampling and data collection in a recent case.