There are dozens of crime dramas on television, as well as a significant number of movies with the same theme. Shows like "CSI" focus on using cutting-edge forensic science to convict criminals for serious crimes like murder and rape.
These shows present forensic evidence as concrete, accurate and irrefutable, and this has led many juries to take it for granted in real-life cases. But the truth is that much of forensic science is not very scientific. In fact, some prominent researchers have labeled several forensic tests as "junk science."
Earlier this year, the President's Council of Advisors on Science and Technology (PCAST) released an illuminating report. It concluded that many commonly used forensic tests have not proven to be reliably accurate enough to be considered scientifically valid. The report specifically criticized forensic tests such as:
- Bite-mark analysis
- Firearms identification
- Footwear analysis
- Microscopic hair comparisons
Unfortunately, these types of forensic tests have been touted in courtrooms for years and used to secure convictions - sometimes without any other corroborating evidence. Judges have discretion about what can and cannot be admitted as evidence in a trial, but they generally defer to the testimony and opinions of scientific "experts" if a test is relatively new or especially complicated. And once the results of a certain test are admitted in few cases, it sets a precedent to let them be admitted in future cases as well.
The forensic tests mentioned above could potentially be validated by empirical studies that test their effectiveness and reliability. But in the absence of such studies, the results of a scientifically questionable test should not be allowed in the courtroom.
The PCAST report is a reminder that evidence in a criminal case may not be as iron-clad as it seems. Therefore, it you are facing criminal charges, please seek the help of an experienced defense attorney who knows how to challenge what many people might take for granted.