Breaking NEWz you can UzE...
compiled by Jon Stimac
Bogus Forensic Expert Bought Degree on Web
MANCHESTER EVENING NEWS, UK
- Jan 18, 2007
...man set himself up as a forensic scientist after buying
qualifications over the internet...
Peru Now Uses AFIS to Track Down Criminals and Unknown Identities
LIVING IN PERU
- Jan 18, 2007 "...we have already detected 500 people who
had a double identity..."
Botched Evidence Lowers Robber's Prison Sentence
HERNANDO TODAY, FL
- Jan 17,
2007 ...new evidence surfaced the night
before trial, further linking suspect to the armed robbery...
Fingerprint Smokes Out Killer
NEW YORK POST, NY
- Jan 17, 2007
...ex-con nearly got away with murder - but a pack of Newports did him
Recent CLPEX Posting Activity
containing new posts
Moderated by Steve Everist
10 years is enough fight for the McKie
clpexco Sun Jan 21, 2007 12:45 pm
Strict Scrutiny Sat Jan 20, 2007 4:32 am
Point Of View: Point Counters and Pseudoscience
Charles Parker Tue Jan 16, 2007 7:54 pm
FinePix S3 Pro UVIR Digital Camera
Dan #845 Mon Jan 15, 2007 5:26 pm
Latent Print / Biometrics Examiner Openings
Lauren Cooney Mon Jan 15, 2007 2:21 am
UPDATES ON CLPEX.com
updates on the website this week.
Craig Coppock brought us a look at what he defines as "Pattern Interference"
in latent print examination.
Cynthia Rennie distills a presentation by Dr. Itel Dror and David Charlton
at the recent ABFDE seminar.
The Effect of Contextual
Information / Why Experts Make Errors
Lecture Notes by Cynthia Rennie
Presentation by Dr. Itel Dror and David Charlton
The Effect of Contextual Information
Dr. Itel Dror, researcher at the University of the Southampton School of
Psychology, discussed the results of some of the experiments that he and his
colleagues have conducted regarding the decision-making process that experts
undergo when examining and comparing fingerprints.
In one of his studies, Dr. Dror examined the effect that contextual
information might have on the fingerprint examiner. He obtained the
cooperation of five fingerprint experts who agreed to take part in the study
without knowing exactly when they would be tested. The researchers collected
pairs of fingerprints from archives that the each expert had examined and
judged approximately five years earlier as a clear and definite match. For
the purposes of the study, these very same pairs of fingerprints were
re-presented to the same experts, but this time they were told that the pair
of prints was the one that was erroneously matched by the FBI as Brandon
Mayfield, the accused "Madrid bomber". This created an extraneous context
that the prints were a non-match. (The researchers ensured that none of the
participants were familiar with the "real" Madrid/Mayfield fingerprints.)
The fingerprint examiners were asked to decide whether there was sufficient
information available in the pair of prints to make a definite and sound
decision, and, if so, what that decision was - i.e. match or non-match. The
examiners were allowed to adjust the magnification and lighting of the
prints, and were given as much time as they wanted for the examination. They
were also told to ignore the context and background information, and to
focus solely on the actual print in their evaluation and decision-making.
Of the five participants, only one remained consistent and judged the prints
to be a match. The other four changed their identification decision from the
one that they had made five years earlier. Thinking that they were looking
at the Mayfield fingerprint, three of the four examiners determined that the
two prints were not a match, and the other decided that the prints offered
insufficient information to make a definite decision.
The researchers considered several possible reasons for the changes of heart
exhibited by the four examiners, including practitioner error;
methodological and procedural problems in the way that the examiners were
trained and identifications were conducted; and the possibility that the
scientific basis of fingerprint identification was flawed. They concluded
that the findings of inconsistent identification decisions may reflect
cognitive flaws and limitations in conducting objective and independent
processing and evaluation of the information. They warn that other
extraneous contextual effects (such as emotional context; 'group think';
biases; hopes and expectations; self-fulfilling prophesies and peer
pressure) can also have an effect on the examiner.
The report concluded by suggesting that vulnerabilities in fingerprint
identification can be minimized by better initial selection and screening of
fingerprint examiners; by appropriate training and professional development,
and by the adoption of methodological procedures that adequately address
potential pitfalls. The fact that one examiner did not change their findings
demonstrated to the researchers that it was possible to be objective even in
the face of overwhelming contextual information.
Why Experts Make Errors
Dr. Itiel Dror
In an article published in the Journal of Forensic Identification(600/56(4),
2006), Dr. Itiel Dror and David Charlton examined the role that
psychological and cognitive factors may play in errors made by latent
The fact that latent fingerprint examiners are human allows for the
possibility that errors may result from the way the brain processes
information and makes decisions. The authors designed a study to investigate
the possibility that inherent psychological and cognitive mechanisms
predispose fingerprint and other forensic identification experts to commit
The authors obtained the cooperation of six fingerprint experts from their
pool of volunteers. Each expert had a minimum of five year's experience in
examining latent prints as their primary duty. Each was highly trained,
certified by a nationally-recognized independent authority, and had
successfully completed proficiency testing. None of them had been the
subject of a competency review. They were told that their conclusions would
be used for an assessment project intended to look at problematic prints and
A unique set of eight pairs of fingerprints was prepared and tailored for
each of the participants. Each set was comprised of fingerprints that the
subject had examined in the past. Four pairs of prints had been judged as
individualizations and four pairs of prints had been judged as exclusions.
Two of each of the pairs were relatively difficult to judge, and two were
relatively easy to judge. All of the fingerprints had been obtained from
actual crime scenes.
In contrast to a previous study where the participants were told that the
prints they were examining were from the Mayfield(Madrid Bombing) case, in
this study the authors used a more subtle approach. In two pairs of latent
comparisons that that the expert had judged to be exclusions in the past,
the participants were told that the suspect had been arrested or had already
confessed to the crime. In two pairs of latent comparisons that the expert
had judged to be individualizations in the past, the examiners were told
that the suspect had been in custody on other charges at the time of the
offence. The remaining four of the pairs of latent comparisons were used as
controls and no contextual information was provided for them.
When the results were tabulated, it was found that only two out of the six
participants remained consistent across the eight experimental trials. Their
findings were the same as they had been when they first examined the pairs
of fingerprints in the past. The other four changed their findings - one of
the experts changed their findings in three cases, while three others
changed their findings in one case. In most instances, the changes took
place when the participants examined the more difficult latents, and changed
their findings from 'individualization' to 'exclusion' or 'cannot decide'.
In one case, the examiner changed a previous decision from 'exclusion' to
The data collected in this study demonstrates that the findings of
fingerprint examiners could be vulnerable to contextual information. This
vulnerability is most pronounced when dealing with difficult comparisons,
but can also be a factor when performing routine comparisons. The fact that
two of the six participants did not change any of their findings shows that
it is possible to overcome the influence of contextual information.
The authors concluded that more research is needed in a wide range of issues
pertaining to individualization, including the aptitude and training of
fingerprint examiners; the procedures in place that can filter out
contextual bias; and the correct use and integration of technology. The
authors believe that the results of such research would reduce the numbers
of errors being made.
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