In 2016, the President’s Council of Advisers on Science and Technology (PCAST) issued a report on the reliability of various forensic science techniques. The report was earth-shaking for the forensic science community.
It concluded that there was insufficient scientific underpinnings for a wide variety of forensic techniques that have commonly been used in the criminal justice system, including:
- Bullet lead examination
- Latent fingerprints analysis
- Hair analysis
- Bite mark comparison
- Firearms and spent ammunition analysis (ballistics)
- Tire track analysis
- Footwear analysis
- Tool and tool mark analysis
- Handwriting analysis
These techniques share a common feature. They all purport to match features from a crime scene sample with a sample from the defendant. PCAST concluded that feature-comparison techniques are, overall, unscientific and unreliable. They are highly subjective and prone to confirmation bias. Moreover, forensic examiners routinely overstate the scientific case for their findings when testifying in court.
The report urged stakeholders in the federal criminal justice community to take action to reduce the influence of these unscientific techniques on court cases, or at least to limit the testimony. Objective, scientific methods for performing these types of analyses are urgently needed. When these analyses are performed, prosecutors should ensure that they have been performed properly and that testimony about the results is not exaggerated.
If a scientific basis for objective results is not developed for feature-comparison techniques, they should not be admissible in court at all.
Unfortunately, the PCAST report was largely abandoned by the subsequent administration. Forensic science was not a priority.
Now, however, President Biden has appointed one of the authors of the PCAST report to be director of the White House Office of Science and Technology Policy. His name is Dr. Eric Lander, and he is a mathematician and molecular biologist.
Flawed forensic evidence leads to wrongful convictions
According to the National Registry of Exonerations, about a quarter of all DNA-confirmed exonerations involve convictions garnered by use of faulty or misleading forensic testimony.
The unquestioning use of feature-comparison techniques and the exaggeration of their certainty are urgent issues. People are being convicted every day based on testimony about shared features. We hope that Dr. Lander and others in the administration will make forensic science reform a priority.
