Senator Wiener’s Legislation to End Wrongful Convictions Resulting from Faulty Expert Witness Testimony Passes Senate

January 26, 2022

SACRAMENTO - Senator Scott Wiener (D-San Francisco)’s Senate Bill 467 passed the Senate today with a bipartisan vote of 30-3. SB 467, the End Wrongful Convictions Act, would amend the standards used for evaluating expert testimony and forensics in court pre- and post-conviction. Faulty forensic and scientific evidence, provided by expert witnesses,is the second most common reason that individuals are wrongfully convicted. Today, courts have discretion over which expert testimony is admissible. Studies show that courts accept most forensic science and expert testimony without sufficient scrutiny, leaving significant room for imprecision and human error. This error leads to the high rate of wrongful convictions. Expert testimony that fails to rely on sound logic should not be considered in court.

SB 467 clarifies that the definition of false testimony includes opinions based on flawed scientific research or outdated technology that is now unreliable or moot, and opinions about which a reasonable scientific dispute has emerged regarding its validity. SB 467 also clarifies that expert opinions that fail to use valid methodology, research, peer-reviewed studies, or scientifically sound data do not satisfy the requirements for admissible testimony.

This legislation additionally strengthens the grounds on which people can seek post-conviction relief if they have been wrongfully convicted based on unreliable expert testimony. This provision will help exonerate innocent people across California.

For example, recent studies from the National Academy of Science (NAS) and cognitive neuroscientist Dr. Itiel Dror have proven that fingerprint analysis, often part of expert witness testimony, is highly unreliable and subject to cognitive bias. The NAS also looked at what is known as the “CSI effect,” where jurors tend towards “unrealistic and preconceived notions about the availability and precision of forensic evidence in criminal trials” based on portrayals of expert witnesses in popular culture.

SB 467 is part of a larger slate of the California Innocence Coalition’s reform bills. Previously, Senator Wiener authored SB 923, which ensures that law enforcement use evidence-based procedures when obtaining eyewitness identification. Eyewitness misidentification is a leading contributor to wrongful convictions proven with DNA evidence. Before SB 923 was signed into law, California had no statewide best practices for eyewitness identification and there were no evidence-based standards in place. 

SB 467 is sponsored by the California Innocence Coalition, which includes the Northern California Innocence Project, Loyola Project for the Innocent and the California Innocence Project.

“Experts testifying in our courts need to rely on sound science and logic, or their testimony should not be admissible,” said Senator Wiener. “Innocent people’s lives depend on the standards we set in our courts. Faulty forensic science is a major reason that people are wrongfully convicted of crimes – and that is a moral stain on our state. The End Wrongful Convictions Act will help make our state more fair and just.”