1. Jay A. Siegel, PhD Emeritus Professor of Forensic Science - Michigan State University Adjunct Professor of Forensic Science – Indiana University Purdue University Indianapolis

2.  Validity of Methods of Analysis  DNA – methods of analysis proven to be valid: taken from medical science  Chemical identification – proven to be valid: used for years in analytical chemistry  Drugs and toxicology  Explosives and accelerants  Paints, coatings, plastics, other materials  Pattern evidence - arose from police science. Scientific validity has not been established  Beware validation by case work  Not completely validated ≠ invalid!

4.  Firearms Lands and grooves: class characteristics Stria: individual characteristics

5.  Fingerprints Pattern type: class evidence Minutia: individual chracteristics

6.  Handwriting Overall handwriting: class characteristics Details of handwriting: Individual characteristics

8.  Some types of bias  Situational – crime labs located in police departments  Cognitive – Examiner knows too much about the case  Confirmational – one examiner confirms results of another. 2 nd examiner knew the results of the 1st

9.  Confirmational Bias at Work: The Brandon Mayfield Case

10.  The Case  Terrorist bombing in Madrid, Spain  Police recover partial fingerprint at scene, send photograph to FBI to develop suspects through IAFIS system.  Brandon Mayfield’s print comes back as 4 th best hit  He had recently converted to Islam, wife was Egyptian  Suspicion fell on him and he is arrested Brandon Mayfield

11.   FBI examiner declares that Mayfield’s print matches photograph of recovered print  2 nd FBI examiner gets file including 1 st examiner report and confirms conclusions  3 rd FBI examiner gets file including 1 st and 2 nd examiner reports and confirms conclusions  Mayfield retains independent fingerprint expert, who obtains all FBI files. He confirms conclusions The fingerprint examinations

12.   Madrid police capture terrorist and confirm fingerprint match  FBI sends fingerprint team to Madrid. They agree with Madrid PD and Mayfield is released.  He sues federal government and is awarded $4M The fallout

13.  Ppartial fingerprint lifted from Madrid bombing scene The Fingerprints

15.  Issues AccreditationCertification  Not mandatory  Patchwork of standards: many organizations offer, but the standards are all different  Not mandatory  Patchwork of organizations that offer certification  Not tied to a licensure so no revocation of ability to practice forensic science

17.  Problems  No standards  Can be used as “evidence of the facts therein”  Many are little more than certificates of analysis  Not real scientific reports

18.  Where do we go from here?  Role of the NAS report  More research into how to validate comparison techniques  Clearly and unambiguously identify terms  Develop standard, validated methods for analysis  Recognize and minimize bias  Write scientific lab reports  National Commission on Forensic Science

19. Questions?