Do inconclusive forensic decisions disadvantage the innocent?

Area of Science:

• Forensic Science
• Legal Psychology
• Criminal Justice

Background:

• Inconclusive forensic decisions may unfairly disadvantage innocent individuals in legal proceedings.
• The impact of inconclusive forensic evidence on legal judgments requires thorough investigation.

Purpose of the Study:

• To examine if inconclusive forensic decisions lead to more incriminating legal judgments than clearly exculpatory ones.
• To investigate the underlying mechanisms, such as confirmation bias or communication errors, behind the effect of inconclusive forensic evidence.

Main Methods:

• Two experiments involving mock jurors (N=492 and N=1,002) were conducted.
• Participants evaluated cases with varying forensic evidence outcomes: match, no-match, inconclusive, unsuitable, or no evidence.

Main Results:

• Inconclusive decisions resulted in less incriminating judgments than 'match' but more than 'no-match' forensic decisions.
• Inconclusive evidence was interpreted similarly to cases with no forensic evidence or unsuitable evidence, suggesting a communication error.
• The risk of wrongful conviction is heightened when inconclusive forensic evidence replaces a clearly exculpatory finding.

Conclusions:

• Inconclusive forensic decisions can pose a risk to the innocent by preventing a definitive exculpatory outcome.
• Findings suggest that the interpretation of inconclusive forensic evidence may be influenced by communication errors rather than perceptual accuracy or confirmation bias.