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Cop Says Prints Not on Weapon
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CHICAGO TRIBUNE, IL
- Jan 10, 2008
- ...as many as 44 prints were found on the entrance door to the
condominium...
Killer Asks For New Look At Case
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HARTFORD COURANT, CT
- Jan 9, 2008 -
...state police fingerprint expert used new technology to eventually
assist in matching a print...
Crime Lab, Morgue Opens –
IDAHO PRESS-TRIBUNE - Jan 8, 2008
...more than six times the space of its previous home, the Canyon
County Forensics Complex will open its doors for business...
Fingerprint Solves 2004 Burglary
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WCAX-TV,
VT
- Jan 7, 2007
...police
lifted a fingerprint at the scene and sent it to the crime lab and
last month... |
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clpexco 748 Sun Dec 16, 2007 3:36 pm
Body fluids on black bags
Philip Bekker 17 Sun Jan 13, 2008 5:16 pm
Evidence Fabrication in South Africa
Pat A. Wertheim 5342 Sun Jan 13, 2008 3:30 am
Calls for Inquiry to be scrapped
Daktari 5900 Sat Jan 12, 2008 9:01 pm
Zero Error Rate vs. No Error Rate
Michele 1071 Sat Jan 12, 2008 3:57 pm
JFI Commentary
Charles Parker 241 Fri Jan 11, 2008 5:06 pm
2006 Article from Judicature Journal - Improving Reliability
Steve Everist 64 Fri Jan 11, 2008 4:13 pm
Fingerprint Society Website
fpsociety 475 Fri Jan 11, 2008 12:21 pm
Paw prints point to dog in shooting death of Baytown teacher
Gerald Clough 215 Thu Jan 10, 2008 2:45 pm
One Of Ours-
Ann Horsman 438 Thu Jan 10, 2008 2:28 am
They Walk Among Us
Charles Parker 3706 Tue Jan 08, 2008 12:12 am
Need published studies on results of casing processing...
Amy Miller 358 Mon Jan 07, 2008 11:07 am
Zero Error Rate Methodology
Charles Parker 846 Mon Jan 07, 2008 1:29 am
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UPDATES ON CLPEX.com
Updated the Fingerprint Interest Group web page with FIG #
28.
Updated the CLPEX.com Complete Consultants
Worldwide page... more on what these updates mean in the near future!
Inserted KEPT (Keeping Examiners Prepared for Testimony) #2 - Blind
Verification - Explanation, at the end of the Detail.
_________________________________________
we looked at the NIST CONOPS in their upcoming
latent print technology evaluation.
we review a debate on
confirmation bias and cognitive issues in fingerprint identification
recently published in Fingerprint Whorld, and represented here through Fair
Use. This includes a letter published by the Chair of the Fingerprint
Society, a response (Dror, I.E. & Charlton, D., 2007, "Improving perception
and judgment: An examination of expert performance"), additional comments
and criticisms, and a response (Dror, I.E. & Charlton, D., 2007,
"Methodological and conceptual problems in measuring and enhancing expert
performance").
_________________________________________
Letters to the Editor
FINGERPRINT WHORLD
by Martin Leadbetter
Response by Itiel Dror & David Charlton
Page 230 FINGERPRINT WHORLD Vol 33 No 129 September 2007
Dear Sir,
Having read the article in the last issue of Fingerprint Whorld authored by
Dr Itiel Dror and David Charlton, I feel I need to make a couple of
observations. What concerns me seriously is the report that emotional
influence is a factor that can bias perception and judgment. I note that
so-called ‘fingerprint examiners’ were influenced in their decision making
process by stories and photographs relating to the crimes from which they
had been asked to undertake fingerprint comparisons. I do not intend getting
involved in any lengthy pseudo dialectic about this issue other than to say,
that any fingerprint examiner who comes to a decision on identification and
is swayed either way in that decision making process under the influence of
stories and gory images is either totally incapable of performing the noble
tasks expected of him/her or is so immature he/she should seek employment at
Disneyland. I have no knowledge of where these ‘examiners’ originate, but
would certainly not want them on my staff. I would hope that they are not
employed within a UK fingerprint bureau, (in fact, I hope they’re not
employed in any bureau) but if they are, then some serious remedial action
needs to be taken immediately to ensure that they discontinue putting
fingerprints and the public at dire risk.
I do not totally disagree with the suggestion that an examiner might be
influenced in his/her decision making process, but in all my 40 years
service in fingerprints I can categorically state that I never knew of any
examiner changing his or her decision because the crime was nasty or
unimportant or had been swayed by a gruesome photograph. The rumoured
instances that I have heard of have reportedly occurred when either a senior
officer has leant over a junior expert’s shoulder, adding undue pressure to
get a result or when an examiner has assumed that the previous competent
checkers have done a correct job and he doesn’t make a correct analysis
before reaching his/her decision.
Personally, I believe that this sort of reporting unnecessarily damages the
true state of fingerprint identification. We all know that no system in any
discipline can ever be absolutely perfect and flawless when humans are
involved in it’s operation, but let’s be real. Can any other process boast
such a reliable and highly accurate record of success? Certainly not the
Health Service, where occasionally it has been reported that literally
thousands of wrong diagnoses are sent out to unwitting patients. And I do
find it rather unsavoury that those within our own ranks, who ought to know
better and are aware just how reliable the fingerprint system is, continue
to provide fuel for those within the media and Press who seem to relish
attacking what is the most valuable tool in the investigating officer’s
armoury.
Yours faithfully,
Martin Leadbetter FFS RFP BA (Hons)
Chairman – The Fingerprint Society
************************************************************************************************
Response FINGERPRINT WHORLD Vol 33 No 129 September 2007 page 231
Improving perception and judgment: An examination of expert performance
Itiel E. Dror and David Charlton
We are very happy and grateful for the opportunity to have an open forum to
hear and respond to issues of concern regarding our research, as raised by
the Chair of the Fingerprint Society. The fingerprint domain can only
advance by considering new ideas and perspectives by discussing and
examining them in an open and scientific way. Genuine self-reflection and
being critical of one's own work is essential if one wants to improve. Many
times it is unpleasant, but it is necessary, and we welcome it in regards to
our own work and suggest you welcome it in the domain of fingerprint
examination. We welcome the comments and criticisms raised by the Chair of
the Fingerprint Society as a response to our paper Charlton, Del Manso, and
Dror (2007). His comments can be divided into two categories: First,
concrete and material comments, that
require us to respond by explaining our research methodology,
clarifications, reconsidering our analysis and
conclusions, and so forth. The second are comments that are defensive and
personal, which do little to advance our research or the fingerprint
community. The former type require us to provide clarifications because the
comments are legitimate and essential criticism that pull us all together to
a unified platform that we can use to learn and advance for the benefit of
everyone. The latter type of comments deserve dismissal because they do not
progress the debate in a meaningful way, and in fact are harmful as they
reflect a defensive, unscientific, and unprofessional approach.
The comments that need mere clarifications arise from lack of understanding
of our research, or from the lack of clarity on our part in explaining our
work. Either way, we think it is a good opportunity to clarify these issues.
The concern that is characterised as most “serious” relates to “emotional
influence” of “fingerprint examiners” by “stories and photographs”. We must
clarify that our studies using stories and photographs were not conducted on
fingerprint examiners (as clearly stated in our article, see Dror, Peron,
Hind, & Charlton, 2005). We should note that there are good scientific
reasons to believe that such factors do in fact affect expert judgements
(not only fingerprint examiners, but also in any expert domain that relies
heavily on human perception and judgement).
However, this has not yet been established or examined in our research. Our
research does include studies with fingerprint experts, and these do examine
and establish that contextual influence can bias fingerprint examiners, but
these studies employ non-emotional contextual information (see the details
in Dror, Peron, & Charlton, 2006, and Dror & Charlton, 2006).
We do agree, whole heartedly, with the Chair of the Fingerprint Society’s
comment that “serious remedial action needs to be taken immediately” to deal
with any psychological influences on fingerprint judgements. Where our
opinions diverge is that the Chair of the Society dismisses the mere
existence of such influences, ignoring a whole set of well established
research in a variety of expert domains, as well as more recent
studies directly examining fingerprint experts. He focuses his attention and
effort on dismissing and denying the problem rather than taking the
necessary actions to deal with it.
As a second line of defence he personally attacks and insults experts,
attributing any such influences to their personal shortcomings, calling them
“immature” and “incapable”, and saying they “need to seek employment in
Disneyland”. These “remedial actions” do nothing page 232 FINGERPRINT WHORLD
Vol 33 No 129 September 2007 to address and deal with the basic
psychological and cognitive influences that affect
fingerprint examiners. Not stopping here, he also engages in a personal
attack on the experts who
are trying to research and deal with the problem by characterising their
efforts to improve work in the
fingerprint domain as “unsavoury” and that they “ought to know better”.
These kinds of comments should be dismissed, because not only do they not
advance and promote the fingerprint domain, but also they are harmful to it
as they reflect defensiveness and a lack of openness for scrutiny. It is
also demonstrable of a lack of professional and scientific approach (not to
mention that they are unfair and insulting to the individuals involved).
Although he acknowledges that “an examiner might be influenced in his/her
decision making process”, he “categorically states that he never knew” of
cases of examiners who were influenced by context. The fact that he never
knew is purely an epistemic claim reflecting his knowledge, rather than an
ontological claim reflecting what actually exists. In other words, not
knowing is a weak justification to claim that it does not exist. Especially
when you have not engaged in examining if it exists, have not been open
minded to the
possibility that it exists, and have dismissed a priori attempts to examine
it, while adding insult to those who did. We do not doubt that he is sincere
that he himself has never known of such cases, but it may well be that he
has not encountered them, but that they do exist nevertheless; it may also
be that he encountered them, but did not recognise them for what they were.
What is clear from his letter is that he is not open to examining and
finding out if they exist, and taking actions to deal with it. This approach
– and not our research – is what is harmful to the fingerprint domain.
Exposing weaknesses and dealing with them does not cause the “unnecessary
damage”. There is damage, and it will increase, unless the fingerprint
community adopts a more scientific approach. Such an approach entails not
only being open to scrutiny, but also embracing and encouraging it. It is
not an easy way,
but it is how any domain improves and advances.
Indeed, the Chair of the Fingerprint Society is correct that medical doctors
make mistakes too. We have repeatedly said, and will say again, that the
problems we expose underlie a whole set of expert domains (and there is
scientific research demonstrating this in the medical domain too). In fact,
these issues pertain to any human, as they arise from the architecture of
human cognition (see, Dror 2005). The claim that these types of mistakes are
more common in the medical domain (as claimed by the Chair of the Society –
we have no
data to support or refute this claim) is a weak defence and unhelpful at
best. Any errors made by fingerprint examiners, as rare as they may be (in
absolute terms or relative to medical experts), need to be researched and
understood with an open mind and an undefensive attitude. Then, based on the
scientific findings, “remedial actions” should be taken as much as possible.
Finally, to address the concern that our research “provide fuel for those
within the media and press who seem to relish attacking” this domain. First,
we are here to advance and improve the domain, not to attack it. Sometimes
moving forward requires acknowledging problems. Second, we have minimal
control on how the media and press use our publicly available research.We go
to great lengths to explain to the media that
fingerprint examination is for the most part very reliable (see, for
example, the BBC News Night interview on the reliability of fingerprint
examination, http://users.ecs.soton.ac.uk/id/bbc.html). Third, great damage
is done to the fingerprint domain not by our studies and research, but by
the attitude and defensive responses to it, as exhibited in the letter from
the Chair of the Fingerprint Society.Aprofessional and scientific response
to the media by the fingerprint community will FINGERPRINT WHORLD Vol 33 No
129 September 2007 page 233 only enhance this domain. Such a response could,
for example, say “We have read this research and are learning from it how to
further advance the reliability of fingerprints”, “We welcome such research
and are determined and committed to improving our work”, or even, “In fact,
one of the leading researchers is a fingerprint examiner himself, and we
encourage all our examiners to continuously question and scrutinise our
practices because this is the only way to guarantee fingerprint examination
of the highest standards”. These kind of responses will reflect well,
advance, and add respect to the domain in the eye of the media. In contrast,
responses, such as “any examiner that may be influenced by emotional context
should seek employment in Disneyland”, “such research is unsavoury and our
examiners ought to know better than to take part in it”, are responses that
are the cause of the harm.
We want to thank the Chair of the Fingerprint Society for taking the time to
express his concerns, and to thank the editor of the journal for agreeing to
have such an open debate. We hope that these exchanges of views will
contribute to establishing a joint platform and agenda for research aimed at
understanding and enhancing fingerprint expert decision making.
REFERENCES (can be downloaded from http://users.ecs.soton.ac.uk/id/biometrics.html):
Charlton, D., Del Manso, H., and Dror, I.E. (2007). Expert error: The mind
trap. Fingerprint Whorld, 33, 151-155.
Dror, I.E. (2005). Perception is far from perfection: The role of the brain
and mind in constructing realities. Brain and Behavioural Sciences 28 (6),
763.
Dror, I.E. & Charlton, D. (2006).Why experts make errors. Journal of
Forensic Identification, 56 (4), 600-616.
Dror, I.E., Charlton, D. & Péron, A.E. (2006). Contextual information
renders experts vulnerable to make erroneous identifications. Forensic
Science International, 156 (1), 74-78.
Dror, I.E., Péron,A., Hind, S., & Charlton, D. (2005).When emotions get the
better of us: The effect of contextual top-down processing on matching
fingerprints. Applied Cognitive Psychology, 19(6), 799-809.
************************************************************************************************
Page 234 FINGERPRINT WHORLD Vol 33 No 129 September 2007
Further compiled questions for Dr Itiel Dror, David Charlton and Hannah Del
Manso:
1. The profile of the sample group has been questioned. The subjects were
predominately young, female and drawn from a narrow geographical area (and
if the location of the examiners was similar then does this also bring into
question the possibility of a narrow range of training, working procedures
and environmental
influence?) as well as being volunteers. Is this sample group, which is not
representative of the wider fingerprinting professional body in age, gender,
experience or location sufficient in range or in size (only 5 subjects) to
extrapolate onto the entire fingerprint profession?
2. It is well known within the fingerprint profession that people behave
differently in different circumstances – i.e. under test conditions some
examiners perform worse FINGERPRINT WHORLD Vol 33 No 129 September 2007 page
235 than they would if they were performing the same work in their daily
life in
the bureau. Given that this was not an evaluation of analysis of the normal
work they performed for 99% of the year, and were instead decisions on
supposedly ‘controversial’ cases (the kind of high profile, high pressure
work that they may not be used to dealing with) are the results
representative of the routine work
done in the fingerprint bureau? Were all of the subjects working in the same
environment, with the same
equipment, under the same time pressures as they would experience in the
bureau and were the materials presented to them in the same format that they
see on a daily basis?
3. Should it be noted that the change in results was from ‘Identified’ to
‘Not Identified’ or from ‘Identified’ to ‘Insufficient’? In the fingerprint
profession the ultimate misdemeanour, other than a deliberate falsification
of evidence, is to Misidentify. Stepping back from a previous decision to
identify a mark (especially when you are unaware that you have previously
identified it) to declare it non-ident or insufficient is quite different
from declaring non-matching marks identified. In the profession missing an
ident is treated very differently from misidentifying – both for the
fingerprint practitioner and crucially in the consequences for the victim of
the mis-identification – yet your study treated any change in decision
equally, regardless of the working culture. Should you have taken this
cultural influence
into account?
4. One of the criticisms levelled at the authors of this work is that it
places weapons in the hands of defence lawyers that could enable them to
attack the fingerprinting profession. Much of the work currently being done
into fingerprints is at an early stage. Indeed, the work into expert bias or
probability based evidence may not create a fully rounded picture for a
decade or more at the current rate of research. Are you at all concerned
that these preliminary studies may be twisted in the courts to misrepresent
the strength and validity of fingerprint evidence?
************************************************************************************************
Response:
Methodological and conceptual problems in measuring and enhancing expert
performance
Itiel E. Dror and David Charlton
Measuring and enhancing expert performance is a challenging task. Many
domains avoid scientifically quantifying performance level, let alone
examining decision making and error. However, for any expert domain, be it
medical experts, military fighter pilots, police officers, or forensic
experts, one must study and understand the underlying expertise (see Dror,
Kosslyn & Waag, 1993). With proper measurements, better understanding can be
achieved, which is a prerequisite for minimising errors and enhancing
performance. Our
research is working to achieve these goals, but it is dependent on the
cooperation and an open dialogue with the experts in the field. We would
like to take this opportunity to thank all the experts, worldwide, who
support the scientific investigation into expertise, both by taking part in
our empirical data collection and by continuously giving us constructive
feedback on our work.
Below we specifically respond to the concerns raised about our research. We
are limited in space and thus can only partially address the issues here
within the limited space allocated to us. However, we encourage and invite
the readers who want to hear or ask more to feel free to contact us (Dave:
david.charlton97@btinternet.com, Itiel: id@ecs.soton.ac.uk). The first
concern in this discussion relates to the participants in our studies. The
use of “predominately young females drawn from a narrow geographical area”
relates only to our first study (Dror, Péron, Hind, & Charlton, 2005). This
participant pool (undergraduate university students) is the standard used in
most psychological research, worldwide. Like any study, the generalisability
from the sample to other populations is an issue to consider. If the
findings derive from basic cognitive mechanisms (like the study cited
above), then one can be quite confident that the findings do apply to other
populations. However, in our other studies we specifically changed our
sample of participants to address this problem and we used experienced
latent print examiners that were representative of the wider fingerprint
community around the world.
The first time we studied latent print examiners we only used five
practitioners. This was in the Dror, Charlton, and Péron (2006) study. In
another study (Dror & Charlton, 2006) we used another set of examiners, this
time six, thus giving a total of 11 examiners. Is this enough? How many
participants are enough? We would need much more space than we have
here to explain and justify our methodology. In short, the number of
participants needed to justify scientific findings depends on many factors.
Sometimes a single participant is sufficient (e.g., a case study or people
with brain injuries, see, for example, Kosslyn, LeSueur, Dror, & Gazzaniga,
1993), and sometimes 10,000s of participants are needed (as in the study
showing the effect of aspirin on the heart). The correct number of
participants is determined by the effect size, methodology used, the
statistical contribution and significance of each data point and
participant, statistical power, variance and distribution of the data, the
number of factors and degrees of freedom in the statistical model, and a
host of other factors. Our studies with latent print examiners have used a
within-subject experimental design in which participants are compared to
themselves, and thus act as their own control. This is a very strong and
robust methodology that requires fewer participants. Still relating to
concerns about the participants, distinct from laboratory studies in which
researchers can control many of the variables and experimental
manipulations, field research (which is important for learning about
experts’ performance) introduces a variety of limitations and confounds. The
validity and reliability of these types of data collections depend on the
participants not being aware of the purpose of the study and if possible,
that they are even being studied. When participants know they are in a
study, and worse, when they know what the study is about, they perform
differently. Thus, all our studies with latent print examiners were
conducted under very strict scientific conditions to avoid such problems
(see Dror, Charlton, & Péron 2006, and Dror & Charlton, 2006, for full
details). The downside of this is that the sample size is relatively small,
but is nevertheless very powerful and meaningful.
Now in terms of the conditions and environment of testing, we tried, where
possible, and with quite a high level of success, to perform the data
collection under the same environmental conditions as every day and ordinary
work in the fingerprint laboratory. This was especially achieved in the
larger study (Dror & Charlton, 2006) when six examiners were involved in
making 48 judgements. The materials were presented in the same format and
circumstances of normal and routine work. Of course, there is variability in
what ‘normal’ circumstances are, even within a single laboratory; this of
course increases when considering the ‘normal’ circumstances across
laboratories, across regions, across countries, and across continents. As in
any research, in any domain, one has to be careful in how well the findings
are applicable. We have gone to great lengths to use scientific
methodologies and data collection procedures that make our findings
applicable. However, no research is perfect, and ours is no exception to
that. Without the strict stipulations on conditions and design that we used
(for example, if we used participants in an open data collection in which
they know they are being studied, or not using a within-subject experimental
design), we could have easily collected data from dozens, if not hundreds of
fingerprint examiners. But that data would be very limited in robustness and
its interpretation even more problematic. Another concern raised relates to
a distinction between a change in decision from ‘identify’ to ‘exclusion’
(or to ‘insufficient’) VS a change from ‘exclusion’ (or from ‘insufficient’)
to ‘identify’. It is obvious that the latter is an error. If you do not
regard the former as an error, then errors can be eliminated altogether by
never making an ‘identification’ decision. If you never make an
‘identification’ call, then you will never be wrong. However, if you do
regard the former as an error, that raises many issues relating to the
payoff matrix (consequences) of false positive and false negatives (as
correctly detailed within the concern). Personally we think that both are
errors, but of a different magnitude. Scientifically speaking, the
thresholds and decision criteria within the decision model (see, Dror,
Busemeyer, & Basola, 1999) are not symmetrical. Thus, the level of
‘evidential weight’ needed for deciding an individualisation is higher than
that needed for deciding an exclusion (and even lower for deciding
‘insufficient’).
Indeed, in our Dror, Charlton, and Péron (2006) study we only examined a one
way decision change, changing from an individualisation decision. However,
in the larger Dror & Charlton (2006) study we examined both directions of
decision change. Consistent with the point raised in the concern, the
findings (see full details in the study) support that contextual information
and bias can more easily change a decision away from an individualisation.
However, the data also showed that context can bias the decision toward an
identification (although this is more difficult, it can still happen). It
should also be emphasised that we are only interested in data for scientific
academic reasons. For example, we are fascinated by the data that
highlighted consistency of decision making within some examiners (in both
directions of decision), and future studies may help to provide detailed
models of the sort of examiners that are more immune to such biasing
effects. The final concern relates to the impact of the studies within the
criminal justice system. We have addressed this issue in quite some detail
in the last section of our response to the criticism raised by the Chair of
the Fingerprint Society (so to avoid redundancy, we refer the readers to our
response to the letter).
We would like to add here that with the cooperation of the fingerprint
community these research studies can contribute (and already have) to
changes in how examination is carried out, examiners are trained, and so
forth. It is up to us (both researchers and latent print examiners) to work
together to make fingerprint examination as sound and reliable as possible.
For us, it means working with any fingerprint examiner and any fingerprint
organisation to take our findings and use them to enhance fingerprint
decision making. It also means that we work as much as we can with the media
and courts to explain our research and what it really means. For you, the
examiners, it means willingness to participate, cooperate, and support such
research (not necessarily to agree with it!). It also means being open to
hear and to question some of your own accepted ways of working and thinking.
This open debate is definitely a step to achieving our common goals. In the
past few years we have witnessed more and more openness from the fingerprint
community to take on board the delicate issues we research. Our research is
purely guided and motivated to find the truth. We adopt strict scientific
methodology and approach, so as to conduct truly scientific studies.
And more importantly, our interest is genuinely in finding the answers (in
contrast to so called researchers who are just trying to find support for
what they already believe, or to what they think, or hope, is the answer).
This is not always easy, but it is the only way to maintain and improve the
high quality of fingerprint identification in the long run. Your comments
pointed out a variety of issues concerning our research. Some of these are
artefacts and confounds inherent to this type of work, and we are well aware
of them. Other comments have enlightened us and will be useful to us as we
plan and carry out our future research. This set of comments are helpful in
establishing a common platform for debate and research, and will improve the
research in this domain – something we hope we are all happy with and
motivated to do.We are thankful to have had this opportunity to discuss our
research and findings, and hope to continue with a productive dialogue and
interactions.
REFERENCES (can be downloaded from http://users.ecs.soton.ac.uk/id/publist.html):
Dror, I.E., Busemeyer, J.R., and Basola, B. (1999). Decision making under
time pressure: An independent test of sequential sampling models. Memory and
Cognition, 27 (4), 713-725.
Dror, I.E. and Charlton, D. (2006). Why experts make errors. Journal of
Forensic Identification, 56 (4), 600-616.
Dror, I.E., Charlton, D. and Péron, A.E. (2006). Contextual information
renders experts vulnerable to make erroneous identifications. Forensic
Science International, 156 (1), 74-78.
Dror, I.E., Kosslyn, S.M. and Waag, W. (1993). Visual-spatial abilities of
pilots. Journal of Applied Psychology, 78 (5), 763-773.
Dror, I.E., Péron, A., Hind, S. and Charlton, D. (2005). When emotions get
the better of us: The effect of contextual top-down processing on matching
fingerprints. Applied Cognitive Psychology, 19(6), 799-809.
Kosslyn, S.M., LeSueur, L.L., Dror, I.E. and Gazzaniga, M. (1993). The role
of the corpus callosum in the representation of lateral orientation.
Neuropsychologia, 31 (7), 675-686
_________________________________________
KEPT -
Keeping Examiners Prepared for Testimony - #2
#2 - Blind Verification - Explanation
by Michele Triplett, King County
Sheriff's Office
Disclaimer: The intent
of this is to provide thought provoking discussion. No claims of accuracy
exist.
Question – Blind Verification:
Can you explain Blind Verification?
Does your office have a policy on how to do Blind
Verification (when to do it or how often)?
Possible Answers:
a)
Blind verification is a tool we use to insure a conclusion is
reproducible to others. We use it when reproducibility may be an issue.
b)
Blind verification is a tool used to diminish bias from being
introduced into a conclusion. We use it in rare instances when bias may be
suspected.
c)
(State your agency policy).
d)
Blind verification is a time consuming process and we aren’t staffed
to do this. It’s not practical in most offices because of the manpower.
e)
We have a 2 year backlog and can’t realistically add more steps to
our current process.
f)
Blind verification is a tool used in complex conclusions. It’s used
to check for reliability of conclusion but it doesn’t check that a
conclusion was arrived at appropriately or that a conclusion has a
sufficient amount of justification behind it. It’s one of the tools that
can be used to insure good results but scientific peer review checks the
reliability and also checks that the justification behind the conclusion is
adequate.
Discussion:
Blind verification hasn’t been used for very long in
our profession so most agencies don’t have written procedures on when or how
to use it. If your agency has a policy then you could answer accordingly.
If your agency doesn’t have a written policy then you could testify to the
scientific literature that’s available.
Answers a, b, and c: These are adequate
answers.
Answers d and e: These may be correct answers
but they leave the court feeling like more should have been done. It’s true
that blind verification is time consuming and it would back log many
agencies but the courts are not sympathetic to this answer. Imagine how you
would feel if one of your children told you that they knew they should do
their homework but they didn’t have time. Or if an elderly relative told
you that they knew they should take their insulin but they didn’t have
time. You might respond by stating that if something is necessary then they
need to make the time. The same holds true here, blind verification should
be done when it’s needed. The good news is that it’s not needed in most
cases and we need to make sure the courts understand this. Since blind
verification is a tool to protect against bias then it should be used in
complex examinations where bias is a concern (it’s been established that
bias is only a concern when the alternative conclusion is plausible). In
simple comparisons that have a high amount of quality and a high amount of
information, bias isn’t a problem. Using blind verification in standard
cases isn’t a good quality assurance measure it’s just an additional process
that isn’t needed.
Answer f: This is the most comprehensive answer.
_________________________________________
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