Trace Evidence 2011 - Report writing - Marianne stam
Tip: Highlight text to annotate itX
[ Music ]
>> Our first presenter will be Marianne Stam
from the California Department of Justice Laboratory System.
She is presenting on behalf of Helen Griffin who was unable
to attend at the class minute and her presentation will be
about Communicating Conclusions and Customer Feedback.
Our second presenter will be Kornelia Nehse
who is a Forensic Scientist with the Forensic Scientist Institute
in Germany and she will discuss the European viewpoint regarding
report writing.
And our third presenter will be Michael Smith
with the FBI Laboratory that will present
on the U.K. court case decision regarding the interpretations
and conclusions.
So I'll go pass it on to Marianne.
>> Thank you.
Today I am presenting on behalf of Helen Griffin.
I got this at the last minute so I apologize if I stumble here
and there and hopefully don't make too many errors for Helen.
This is a talk that-- that Helen prepared
on communicating conclusions.
So basically, here's the history behind conclusions.
Helen wrote that there'd been attempts to establish databases
that allow for some type
of statistical data especially with class evidence.
The problems however not just with class
but with others involved how rapidly a population
of manufactured materials changes, how difficult it is
to obtain manufacturing data and how much the distribution
of manufactured data can actually vary
from one location to another.
So basically, even without statistics,
conclusions have different way to based
on whether the comparison involves class characteristics
or class plus individualizing characteristics, the quantity
and quality of the evidence and also the commonality
of the evidence in the environment.
In addition, in the absence of statistics, a scale allows
for conclusions that expressed the level
of either certainty or uncertainty.
And scales have been constructed for documents.
There's an ASTM Document E 1658, AFTE, SWGGUN, SWGTREAD, SWGIT,
and the Working Group Marks from Europe have actually come
up with scales for conclusions.
Unfortunately, the scales
for the same wording can mean different things.
And the-- an example of this is the ASTM documents terminology
for inconclusive says zero point of the confidence scale.
SWGTREAD's inconclusive says some similarities noted,
however, significant limiting factors
that do not permit specific association.
AFTE's inconclusive has three different meanings.
The first one says some agreement in individual
and class characteristics but insufficient for identification.
The second one is agreements in class characteristics
without agreement or disagreement
of individual characteristics.
And the third one is the agreement
of class characteristics and disagreement
of individual characteristics with
but they're insufficient for elimination.
So, Christopher Bommarito's scale was introduced
at the 2009 Trace Symposium in which he provided a definition
for each confidence level that he gives for his interpretations
and these are provided in the report.
And even with different scales
in this case there can be no confusion
if you have your definition in the report.
So what Helen's group did was they set up a survey
and they wanted to see which different populations
that they surveyed would prefer either the old style of wording
which was used prior to 2009 that she defines as Style 1
that includes categories identified, probably associated,
could be associated or associated
with another similar source, not eliminated, neither identified
or eliminated-- or eliminated.
And for this Style 1 that was used prior 2009 there was no key
provided in the report
to distinguish what this various degrees of association meant.
And then, in the survey format, they provided Style 2
which was wording used after 2009
and it basically included some of the similar aspects
of strengths of conclusion which you can see here from identified
to very strong support all the way down to inconclusive
and eliminated and these wording that she based her 2009
or the format on for Style 2 is based on work done
by the European Working Group on Marks to attempt
to standardize report wording
for footwear impression examinations.
And they have a scale committee of the ENFSI EWG Marks group
which was established in the third European meeting
for shoe print and tool mark examiners in Sweden in 1999.
And the main goal of the conclusion scale committee was
to produce a conclusion scale that would enable practitioners
to understand the meaning of the conclusions formed by examiners
across Europe taking
into account the different legal jurisdictional regions.
So essentially providing a standardized form
of communicating across the board and it was meant
to be used with collaborative footwear test for the group--
the European Working Group.
[ Pause ]
>> So, for the trace evidence conclusion scale, we have scale
that includes identification with its definition.
Another added scale that the Ventura County Sheriff's Office
added to their scale was a very strong support, strong support,
moderately strong, moderate, and limited.
And basically, the forensic
or the Ventura County Sheriff's Office Forensic Science Lab
Trace section had used the working group mark scale
in some reports to prior to 2009 including 8 levels.
But in 2009 after Christopher Bommarito introduce his
conclusion scale that actually defined each level,
they adapted a modified version of the working group mark scale
to include definitions.
So they combined Christopher Bommarito's idea
with the working group marks scale and with the addition
of one more level which was important and introduced
by Chris Bommarito 'cause it's considered important
to actually add this 'cause trace evidence can involve many
things that include or come close to an identification
and strength but is based solely on class characteristics.
So, part of the-- for their survey,
they actually presented a hypothetical
and in this hypothetical they had green fibers
that were on a nail-- oops.
They had a sweatshirt that was green and they had--
and that was 80 percent cotton and 20 percent polyester.
They provided the hypothetical
as having been examined microscopically
for various features, FTIR and microspectrometry
for the color comparison.
And the fibers from the nail and from the sweatshirt were similar
in all characteristics including blend comparison.
So then they present it in their survey the conclusions, Style 1.
The fibers from the nail originated either
from the green sweatshirt worn by the suspect
or from another source
of similar green polyester kind of fabric.
>> So that was the old style that they used to use.
Style 2 which was the newer style is the following
similarities provide moderately strong support that the fibers
on the nail originated from the green sweatshirt
and these properties include optical properties,
fluorescence, thickness cross-sectional shape,
chemical composition, blend composition, and color.
So, Style 2 would actually be included in the entire--
in the report with a definition of the scales.
So, the feedback they got
from the report writing survey was the following.
When they polled law enforcement,
Style 2 is in yellow and Style 1 is in blue,
you can see for law enforcement to the left, the prosecutors,
then public defenders, then jurors,
all of them pretty much favored overall Style 2
which is the new method of-- including the definitions
and having the-- at the scale of in conclusions.
For law enforcement, they only had 8 responses
which is 25 percent, 6 of which 75 percent
of these responses preferred Style 2 and some
of the comments included easier to digest and understand.
However, there are other comments too
from law enforcement that included Style 1 is easier
to use to draw other connections in the case, easier for jury
to form their own conclusions based on the evidence
and the scientist's testimony.
And for Style 2, it has a great degree
of subjectivity to the conclusion.
However, overall law enforcement preferred the old style.
Prosecutors on the other hand, there were 12 responses and 9
which is 75 percent preferred Style 2.
However, of the 5 major crimes prosecutors that responded,
3 strongly preferred Style 1
and they got some interesting feedback on why.
So the prosecutor preferring Style 1 said that,
"Style 2 gives the defense way too much room for argument
that will just confuse the jury.
Moderately strong support only falls in the middle
of the conclusion scale.
All of those categories
above moderately strong support offer the defense almost
countless ways to disqualify the evidence."
Other comments where, "We deal
with only one relevant standard beyond the reasonable doubt
to use other language when the lab analyst offers her level
of conviction for her conclusion on a particular item
of evidence is at minimum confusing
and not maximum undermining
of the standard the prosecutor is trying to reach."
Other comments were that,
"Moderately strong support is not proof
of beyond reasonable doubt and we all argue corroboration
but the wording trying
to quantify weakens the appeal of our case."
[ Pause ]
>> Public defenders on the other hand, there is only one response
but they preferred Style 2.
They said it provided more detailed information
without the conclusory language
which invades the province of the jury.
The jury pool on the other hand, there were 6 responses and 6--
all 6 of them preferred Style 2.
They said, "The conclusion scale adds a nearly essential
component to the interpretation for the jury member
that allows the juror a much greater grasp of the importance
of the information and how it relates
to other information presented in the case."
[ Pause ]
>> So, in summary, although the majority
of our clients preferred Style 2, a persistent comment was
that they could have originated from word--
wording was actually easier to understand.
So in post survey discussion since the reported objective is
to determine if the fibers on the nail could have originated
from the sweatshirt, the Ventura County decided
to include this wording in the conclusion and as follows.
"The following similarities provide moderately strong
support that the fibers on the nail could have originated
from the green sweatshirt" and that's it.
Helen invites your questions.
[ Laughter ]
>> Your comments and here is Helen's email.
[ Laughter ]
>> So, thank you.
[ Applause ]
