Daubert Motion

What is a Daubert Motion?

The admissibility of evidence is crucial in determining the outcome of a federal criminal proceeding, especially in trials. Expert testimony is vital to resolving many cases because these witnesses provide specialized opinions that can significantly impact a jury's verdict.  

Notably, however, are the issues of what exactly “expert” testimony is and how a federal judge decides which expert testimony is worthy of being heard by the jury. 

Federal judges must ensure the reliability and relevance of all evidence admitted into the trial, including expert testimony. The Daubert motion is the method judges use to separate valid vs. speculative science. It's often a complex procedure in the criminal judicial process.

A Daubert motion is a formal request by one party in a legal proceeding. It's often filed by a federal defense lawyer opposing the admission of expert testimony to challenge the admissibility.

Daubert Motion
A Daubert motion is an attempt to exclude the presentation of an expert's testimony in a trial.

The Daubert motion ensures that only reliable and relevant expert testimony is presented to the court.  It is usually filed before or during the trial, and its purpose is to persuade the court to evaluate whether the expert testimony being offered meets the Daubert standard. It's often part of pre-trial motions.

If you're charged with a crime and federal prosecutors want to bring in expert witnesses to testify against you, your federal criminal defense lawyer might decide to file a Daubert motion to keep potentially substandard testimony from being presented to the jury. 

A Daubert motion is a strategic move by defense lawyers to challenge the validity and reliability of questionable expert testimony or scientific evidence presented by a prosecutor. 

If successful, it can significantly impact the outcome of a case by discrediting specific scientific methods or experts. For example, suppose a court finds a forensic scientist's DNA analysis method unreliable. In that case, the evidence might be excluded.

What is the Daubert Standard of Admissibility?

The Daubert motion is named after a landmark Supreme Court case, Daubert v. Merrell Dow Pharmaceuticals. It's a crucial tool to challenge and possibly exclude scientific evidence federal prosecutors want to present at trial. 

Simply put, the Daubert Standard is a method courts use to decide whether expert testimony should be admissible in a criminal trial. It can be raised when a defense attorney or federal prosecutor believes faulty information is being used. Expert witness testimony can significantly impact a jury, which means evidence rather than personal opinions must support their theories.

Using the Daubert Standard, courts consider several factors to decide if an expert's methodology is valid, such as if the theory can be or has been tested. Further, courts will consider whether their theories:

  • Have been published,
  • Subjected to peer reviews,
  • Have a known or potential error rate,
  • Have maintenance standards controlling its operation and
  • If it has widespread acceptance within a scientific community.

In other words, the “Daubert Standard” gives a trial court judge a way to assess the reliability and relevance of expert witness testimony before the jury hears it.

Can You Challenge Expert Testimony?

A Daubert motion is a legal motion typically filed by a criminal defendant to exclude the testimony of an expert witness or presentation of unproven scientific evidence. 

It's based on the premise that the expert's methods are not scientifically valid or relevant, which derives from the standards in the Federal Rules of Evidence 702, which requires: 

  • Expert testimony must consist of scientific or technical knowledge and
  • It helps a judge or jury understand the evidence.

Thus, if a defense lawyer or prosecutor wants to challenge expert witness testimony in a criminal case, they could file a Daubert motion to force one side to prove the expert is basing their opinion on legitimate scientific principles.

Before the Daubert standard, the rules allowed courts to decide if an expert witness was qualified to testify, and the jury would determine the credibility, which is called the “Frye" standard. 

However, the Supreme Court ruling in Daubert changed this standard and placed more responsibility on judges to ensure the reliability of scientific evidence at trial. Now, the Daubert standard requires that expert testimony must be:

  • Based on grounded scientific knowledge,
  • Relevant to the criminal case and fits the facts,  
  • Reliable and methodologically sound,
  • Tested and subjected to scrutiny.

A Daubert motion is usually filed before trial and might be based on information found in discovery documents, such as expert witness reports. A Daubert motion is different from a motion in limine, which seeks to exclude evidence from jury review and is usually filed before the trial begins and addresses any evidence that might unfairly prejudice the case. 

What is Daubert Hearing? 

Once a Daubert motion is filed, the judge will schedule a Dauber hearing where both sides can make arguments regarding the expert testimony without the jury present

The judge will apply the abovementioned Daubert standard to decide whether the expert testimony should be admissible. As noted, the standards are a series of criteria based on numerous factors, such as the following:  

  • Has the theory or technique undergone rigorous testing?
  • Is there an acceptable error rate?
  • Has the scientific community scrutinized the theory?
  • Has the scientific technique been published?
  • Does the scientific community generally accept the theory?
  • How well does the evidence align with the facts of the case? 

Further, the court will also evaluate whether the evidence gathering followed due process. For example, improper blood sample storage might render subsequent test results unreliable and make it inadmissible.

Suppose the judge grants a Daubert motion. In that case, the expert testimony or scientific evidence may not be presented to the jury. Further, the judge's ruling prevents the prosecution from presenting similar evidence throughout the trial. 

Sometimes, a judge could reject the motion and allow the questionable evidence to be submitted. If this occurs, the defense lawyer must devise a new strategy to challenge the testimony or evidence. Contact us for a free case evaluation if you are under investigation or indicted. The Hedding Law Firm is located in Los Angeles, California.

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