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 California’s Approach to Expert Testimony: Kelly/Frye vs. Daubert

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When dealing with expert testimony, legal professionals must understand the key differences between California’s Kelly/Frye standard and the federal Daubert standard. While federal courts use Daubert to assess expert testimony, California relies on Kelly/Frye. These differing approaches can significantly affect the outcome of a case, and understanding them is crucial for attorneys working in both state and federal jurisdictions.

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The Daubert Standard (Federal Courts)

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The Daubert standard (from Daubert v. Merrell Dow Pharmaceuticals, Inc. 1993) requires that expert testimony be both reliable and relevant. Federal courts evaluate the expert's methodology based on factors like testability, peer review, error rates, and acceptance within the field. The key point is that the judge acts as a gatekeeper to ensure that the expert's testimony is scientifically valid and will assist the jury in understanding complex issues. Daubert is flexible, allowing newer or emerging scientific methods as long as they meet reliability standards.

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The Kelly/Frye Standard (California)

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In contrast, California follows the Kelly/Frye standard, which stems from the 1923 Frye v. United States case and the 1976 People v. Kelly decision. Under this standard, expert testimony based on scientific methods must be generally accepted by the relevant scientific community. This means that if a method is new or novel, it will likely be excluded unless there is sufficient evidence that the scientific community accepts it as valid. The focus here is on general acceptance, not the broader reliability factors used in Daubert.

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Key Differences Between Daubert and Kelly/Frye

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1. Flexibility: Daubert allows for a broader evaluation of reliability, while Kelly/Frye is stricter, focusing on whether a method is widely accepted within the scientific community.

1. Admissibility of Novel Methods: Federal courts may admit new methods if they meet reliability standards, while California courts are more cautious and require general acceptance of the method.

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1. Role of Judges: Both standards require judges to act as gatekeepers, but Daubert gives judges more discretion in evaluating a method’s reliability, whereas Kelly/Frye is more focused on acceptance by experts in the field.

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Why It Matters

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For attorneys, understanding the distinction between the Daubert and Kelly/Frye standards is crucial for handling expert testimony. In federal cases, lawyers focus on proving reliability and relevance, while in California state cases, the emphasis is on demonstrating that the methodology is widely accepted by the scientific community. This distinction can impact how experts are prepared and how challenges to their testimony are made.

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Conclusion

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The Kelly/Frye and Daubert standards represent different approaches to admitting expert testimony, with California requiring general acceptance in the scientific community and federal courts focusing on the reliability of the methodology. Understanding these differences is essential for attorneys practicing in both state and federal courts.