Media & Insights
April 27, 2023
Plaintiffs sued defendants, alleging that defendants’ medication caused them to suffer heart failure. To establish general causation (i.e., whether defendants’ medication was capable of causing the harm plaintiffs alleged), plaintiffs called a medical expert who concluded, based on a single epidemiological study, that defendants’ medication was capable of causing heart failure. Defendants moved to exclude plaintiffs’ medical expert testimony and the trial court granted the motion. Plaintiffs appealed.
The Court of Appeal affirmed. The court held that the trial court did not abuse its discretion in excluding a medical expert’s opinion after finding that the expert did not utilize a reliable methodology for weighing the evidence, but relied instead on a shifting results-based methodology that failed to logically and consistently weigh all relevant evidence. The court noted that “while the trial court may not weigh an expert opinion’s probative value or persuasiveness, it must still consider whether the opinion is logically sound.” The court also held that the trial court did not abuse its discretion in excluding expert testimony on general causation when the expert’s opinion is based on a single study that provides no reasonable basis for the opinion offered. The court noted that “[a] single study rarely, if ever, persuasively demonstrates a cause-effect relationship,” that “[e]pidemiological studies demonstrate only association, not causation” and that before a causal relationship is accepted by epidemiologists and other scientists, it is “important that a study be replicated in different populations and by different investigators.”
