The Mayfield Case
Confirmation Bias
Is It Science?
Error Rates
Wrongful Convictions
100

This European city was the site of the March 11, 2004 subway bombings that triggered Brandon Mayfield's misidentification.

Madrid, Spain

100

This term describes the tendency to search for, interpret, and recall information in ways that confirm what you already believe.

Confirmation bias

100

Saks & Faigman (2008) argue that fields like fingerprint, bite-mark, and hair comparison analysis are "nonscience forensic sciences" because they lack this — theories systematically tested via hypothesis testing.

A basis in the scientific method / empirical validation

100

In Cole's (2006) study of the Boston PD Latent Print Unit, examiner error rates on ADVANCED difficulty prints ranged from 3.3% up to this high number.

15.4%

100

This man was exonerated in 2005 after serving 17 years for sexual assault, following revelations that Houston PD crime lab testimony about hair and blood type evidence was false.

George Rodriguez

200

This many FBI fingerprint examiners originally matched a partial print from the bombing scene to Brandon Mayfield.

3 (a 4th, hired by his own defense counsel, also "confirmed" the match)

200

In the Dror, Charlton & Peron (2006) study, examiners were shown prints they'd matched 5 years earlier and told the prints likely did NOT match. This percentage reversed their own original identification.

80%

200

The 2009 NAS report concluded that, except for this one method, no forensic technique had been rigorously shown to reliably connect evidence to one specific source.

Nuclear DNA analysis

200

This forensic discipline, which compares tooth impressions to skin wounds, showed an error rate as high as 64% in proficiency tests — yet mock jurors estimated its error rate at about 1 in a million.

Bite-mark identification

200

This man was executed in 2004 after being convicted of murdering his 3 children by arson, based on "pour pattern" evidence later shown to have no scientific basis.

Cameron Todd Willingham

300

Spanish authorities eventually matched the print to this real suspect, an Algerian national.

Ouhnane Daoud

300

This proposed reform has examiners compare evidence against a pool of several candidate samples instead of one suspect vs. one crime sample — intentionally mirroring eyewitness lineup procedures.

An evidence lineup

300

This four-letter acronym names the standard fingerprint comparison method criticized for having no consistent, agreed-upon matching criteria.

ACE-V (Analysis, Comparison, Evaluation, Verification)

300

According to the 2016 PCAST report, out of DNA, bite-mark, latent fingerprint, firearms, footwear, and hair analysis, only DNA and (in some forms) this second discipline met scientific validity standards.

Latent fingerprint analysis

300

According to the National Registry of Exonerations, this percentage of the first 330 DNA exonerees had problematic forensic science analysis or testimony involved in their case.

47%