From Galton Points to ACE-V:
One Examiner’s Journey
An Editorial Perspective Disguised as a Research Paper
By Sandra Wiese
Like many other people I have met in the forensic professions, I was not fortunate
enough to begin my career in a mentoring program or internship. I work for a small
department and my in-house training consisted solely of learning how to use the
computer system and being shown where the various offices were. Any and all training I
did have came as a result of my own pursuit of it through courses put on by my local
professional organization and through personal training with professional contacts.
While I would not trade this experience for anything, I do admit it was spotty training at
best and somewhat accidental at worst. I also found out that this is the norm in some
jurisdictions, both near me and throughout the United States.
Just as my colleagues in similarly small agencies do, I wear many hats: crime
scene investigator, latent print developer and examiner, photographer, blood pattern
analyst…butcher, baker, and candlestick maker. Not only do I have to report on these
duties, I am frequently subpoenaed to testify to my examinations and analyses in these
areas. The courts do not much care that I may not be experienced enough to write a book
on any of these topics, they rightfully only care that I have performed my duties with
honesty and integrity and that I have the proper training to perform them correctly. And
here lies the rub. Without a proper mentoring program, I feel that I have not had the
opportunity to develop a thorough enough knowledge in these areas as I might like.
Despite countless hours of my personal time spent reading professional journals and
books and talking with colleagues about the proper or best ways to accomplish my duties,
I can never be sure just what I am missing. How could I be sure I was doing it “right?”
The little personal instruction in latent comparison I received over the years went
something like this:
“See this point here in the latent? Now find that in the inked print. Now find any
other points that match like that. If you don’t find them, you don’t have a match.”
That was about it. I later found out I wasn’t the only person to receive this sort of
instruction. This was or is the norm for a lot of the smaller agencies in my area.
Then in 2001, I signed up for a course called “Ridgeology” because I heard it was
a great class. I had previously learned to count “points” and also that there was no
minimum number that was necessary for an identification. In the same breath, the more
experienced examiners I knew would tell me how they never go into court with less than
[fill in an arbitrary number here] “points” and how they once knew someone who got a
conviction off a comparison with only [fill in an arbitrary smaller number here] “points.”
Imagine my confusion with this “there is no minimum number but this is my minimum
number and you should find a minimum number that you are comfortable with”
philosophy.
Well, I went to this Ridgeology class and found out that you can use the very
pores in the ridges to make an identification! What would they think of next? We were
shown pictures of comparisons with only three “points” and told they were an
identification. Now I believe with all of my heart and mind that no two fingerprints or
other areas of friction skin are alike, but there was no way I was ever going to testify to
something like that. How could I possibly take that to a jury in my county and ask them
to buy it? I believed it, yes, but I could not explain it if my very life depended on it.
During this class, we learned about a “new” process for comparing latent prints
called ACE-V. (Actually, we first tried to learn about “ayzvee”, which is what ACE-V
sounds like coming from a fast-talking Canadian. Then we made him write it down and
it all became clear as…well, you will see.) If my confidence in my abilities to compare
prints was a little shaky before I came to class, after those “three-pointers” he showed us
I was down right terrified. But I did understand that ACE-V was basically the same thing
we had been doing all along, but it was a better way to articulate the process of
comparison and identification. After this class, I added words like “level one detail” and
“insufficient to effect a comparison” to my examination reports. I may have referred to
the presence of level three detail in my reports, but I was still not remotely comfortable
with the idea of ever using it myself. I was still comparing “just points,” but I was
wording it in a more sophisticated way.
About a year went by and I was still comparing points and only points and was
eternally grateful that I did not have to ever testify to more than a negative identification.
I did have confidence in my identifications and did get verification from examiners at
other agencies, but I did not want to have to testify. Along came a Daubert symposium in
2002 and any confidence in my ability to testify crumbled like the Berlin Wall. How
could I possibly be expected to know all of that and still perform at “expert” level in the
other areas of my job?
Shortly after the Daubert symposium, I had the opportunity to take an advanced
comparison course and jumped at it. My hopes had been that this would be the class that
made it all clear. My last chance, really. During this class we discussed the concept of
“no minimum points” and “sufficiency.” I brought up that I did not understand how to
respond to a defense challenge that “sufficiency” was subjective and therefore, not
science. I left the class without an answer to this question. I drove home preparing in my
mind how I would tell my boss that I could not do latent comparisons anymore because I
obviously did not “get” it. I practiced saying, “Would you like to super size that?”
As you might guess, my boss did not fire me and also did not “get” what the
problem was. I was stuck: I still had to do the comparisons and I was still terrified of
having to explain what I did to someone else (read: judge and jury). I felt like a fraud.
Now comes the end of 2003 and I get a latent print in that is clear as a bell. The
problem? Only about four “points” but also one very nice scar running down the center.
Now I did not have suspect prints to compare at that stage, but I looked at the print and
thought, “If I do get a suspect and I do make a match, how can I testify to it if most of my
‘points’ are all up and down the scar?” So I sent the prints to an IAI certified examiner I
know (Mark Beck, CLPE, Alaska Department of Public Safety) and posed this same
quandary to him. Oh sure he would make an identification off the print he tells me, no
doubt. I wanted to know how? I couldn’t possibly testify to it. So he explained it to me
and, a la Lucy Ricardo, I finally got it. It wasn’t the points, it was the way they were
shaped and where they were in relation to everything else, not just how many ridges
separated them. That this ridge goes down and to the right and not up and to the left and
this other ridge is a little bulbous and this other ridge is pointy…Voila. It is not just the
existence or location of various pores or the shape of the ridge edges. If anyone had ever
explained that to me, I must not have been listening because that was the first time “level
three” made sense to me. Holy God I could use level three in a comparison! There was
hope.
But what, I asked him, if this goes to court and that nasty “sufficiency” question
raises its ugly head? Most of the areas of comparison in this latent were up and down the
scar and I was still not prepared to use every single ridge characteristic (bye-bye
“points”) to make my identification, even if I knew it was an identification.
“Sufficiency,” I said to Mark, “is subjective. The subjectivity makes it an art or at the
very least partially an art and not science and there is no way to counter that!” I have
been wrong before, perhaps just never at this level. This was “level three” wrong
thinking, but he made me finally understand. I will tell you how in just a bit…
Now, this very well may be the longest introduction to a “research” paper ever
written, but without knowing the history, it has little overall impact. I have been in this
business for eight years, the last five as a full-time Criminalist with latent print
comparisons as a primary duty. I have had over 250 hours of classroom instruction in
latent development, recovery, classification and comparison. I just understood what is
happening when I compare prints last month. On the off chance that I am not the
dimmest bulb on the tree and that there are others just like me, you had to know the
history.
I would like to explain to you what I now know and maybe why and how this
happened to me:
There are many texts available to explain and illuminate the intricacies of friction
ridge identification science. From Field’s Fingerprint Handbook to Ashbaugh’s
Ridgeology with many more in between. Not to mention all of the professional
publications and I won’t even start on the websites. There is a problem with every one of
these sources: If you read only one, you are not getting a well-rounded education in the
area of identification; if you read more than one, you risk complete confusion because the
terminology is not all the same and the methods used to make an identification are not all
the same. Couple these problems with the absence of an experienced examiner as mentor
(or the presence of an indifferent mentor) and you get a recipe for perfectly poor
confidence in the examiner’s ability to articulate the process involved in a comparison.
One of the most glaringly obvious differences in terminology is the definition of
the term characteristics. I would have thought that this one was a “gimme” because it is
perhaps the most common word used when explaining friction ridge identification
science. Once again, I was wrong. Field defines characteristics as, “the fusion of pores,
length, course, breaks, directions, etcetera, of the ridges form the individual
characteristics of fingerprints (Field, 11).” A pretty advanced definition for a text written
in 1959. But this is a very different definition than the more modern one provided in a
glossary of identification terms published in 2002 by the Scientific Working Group for
Friction Ridge Analysis, Study and Technology (SWGFAST), which defines
characteristics as, “features of the friction ridges. Commonly referred to as minutia(e),
Galton detail, point, feature, ridge formation, ridge morphology (SWGFAST Glossary,
1).”
This definition got me because I (and other people I know) had been going out of
my way to not use the term “Galton details” or the word “points” anymore. I thought
those terms were the “old way” and that they were not to be used now that we had all
these “levels” in friction skin. So now I’m really confused, but I cannot find any
explanation anywhere for all the different definitions. There doesn’t seem to be a text
written just for me. No Fingerprinting for Dummies, no The Idiot’s Guide to Friction
Ridge Identification. I did find out that I am not the first person to notice this. Scott’s
Fingerprint Mechanics states that “There is no common agreement among
authorities…of the different types of ridge characteristics or their terminology (Olsen,
9).” And in 1983, Cowger wrote, “The terms used to describe these characteristics vary
markedly among writers in the field and differ even among examiners (Cowger, 143)…”
While I may know that a bifurcation and a dividing ridge are two words for the
same thing, and while I may be able to tell you how this is so, up until recently I would
not have been able to tell you exactly how “points” and “Galton details” were different
from “level one, two and three details.” And I could not have referred to an authoritative
text for this answer because it is not specifically addressed. If I am so confused, how can
anyone blame a new examiner for being frustrated or an attorney (prosecutor, defense or
judge) for being confused? We can talk shop with other latent print examiners all day
every day and think we have it all in the bag. But unless we can make the rest of the
world understand what we are talking about and doing, all of our talk is relatively
worthless.
Let’s look at that whole attorney problem while we are on the subject…If asked, I
imagine most attorneys (and lay people for that matter) would tell you that they know
only two things about fingerprints: 1) they can be used for positive identification, and 2)
you have to match up at least [fill in a number between about 8 and 12] points. This is
what they know. But wait! There are no minimum points, right? No court has ever said
there was a number, right? An attorney might not get that idea if they used the
Fingerprint Handbook as their reference source, which states this definition: “Number of
Identical Characteristics: it is necessary to identify only the most distinctive
characteristics, rather than each ridge. Most courts consider eight to twelve points of
identity sufficient for convincing identification. (emphasis mine; Field, 127).”
Okay, so if I were an attorney reading this book, I would want the examiner to
come up with a number between 8 and 12 or higher. I might even mention this to the
examiner in a pre-trial conference. Then that examiner might whip out Ashbaugh and
read, “No scientific basis exists for requiring that a predetermined minimum number of
friction ridge features must be present in two impressions in order to establish positive
identification (Ashbaugh, 7).” Now because I am a lawyer, I am going to ask for an
explanation of that one. As an attorney, I am going to want that concrete number. It is
definitive, the jury understands it, and we can move along with the trial right quick:
Wham, Bam, and Thank you Sam. They said there were ten, you’re off to the pen!
Most texts do not seem to address the issue of the difference between having a
minimum number and not having a minimum number. Several sources did mention that
there was no minimum point requirement as a result of the 1973 International Association
for Identification (IAI) pronouncement that this standard had no scientific basis. Other
than reiterating this premise and possibly throwing in a little shameful “pooh-poohing” to
the European countries still using a minimum point standard, most of the texts did not
explain just what this meant in a real world application or how to explain it to a jury.
Only Ashbaugh dares to even address this problem: “The number of points philosophy
had been in use since the inception of the science just over 100 years ago. With this new
doctrine, an opinion of identification could now be based on a varying number of points.
At the time, the change in doctrine appeared to be only a minor adjustment in
identification philosophy, but the consequences were far-reaching. In the beginning this
new doctrine was not fully understood, leading to uncertainty and greater confusion as
opposed to a solution (emphasis mine; Ashbaugh, 2).” He further states, “Most efforts to
describe or defend the evaluative identification process were more an exercise in reciting
rhetoric and dogma as opposed to describing a scientific process. Specific facts and
logical interpretation were conspicuous by their absence (Ashbaugh, 3).” I’ll second that.
My understanding of “no set minimum number” was limited to my having faith in
those examiners in a leadership role in the professional organizations. They had to be
smarter than me, right? So I would have to take their word for it. But since I did not
“get” it, in practice I had to use the “there is no minimum number but this is my number”
approach. It worked for me for the most part. Well, that philosophy combined with the
constant crossing of my fingers and knocking on wood so I wouldn’t be called to testify
about how to compare prints in court. That’s what really worked.
So back to that advanced comparison class and the whole unanswered
“sufficiency” question. After this discussion in class, several people came up to me and
said that they felt the same way. We all had problems defining sufficiency as “enough”
and none of us could explain how the subjectivity involved in our judgment of “enough”
fit in with the concept of a science. The available literature covering this question is not
always clear or even in agreement. Some texts advise that two impressions must
compare identically (emphasis mine; Fields, 125). Others are not so exact “…an
‘identification’ is made when, in the judgment of the examiner the degree of similarity
between two prints is sufficient to warrant that conclusion (emphasis mine; Cowger,
146).” SWGFAST failed to include a definition of “sufficiency” in their glossary of
terms, however they do attempt to define it in their Examination Methodology,
“sufficiency is the examiner’s determination that adequate unique details of the friction
skin source area are revealed in the impression.” Sounds great, but what exactly is
“adequate”?
When I have raised this question in the past in classes and at conferences, I have
been told that maybe I was just being “argumentative” or that I “obviously” did not
believe in the science. I was told, on more than one occasion, that if I believed in the
science then I would know what “enough” was and would I just “let it go.” Well, I did
and do believe in the science. Believe enough to know it can withstand questioning by
little ol’ me. And that these questions mean there is more work to be done to develop a
better understanding for everyone. If I can have these questions after eight years in the
field, imagine the questions of people newer in the field or (gasp!) of those people on the
jury. I would not expect a jury member to believe my testimony just because I told them
it was so, but that is what I would have been doing if I had ever testified to a “sufficient
number of matching characteristics” without being able to explain what exactly this
means.
Maybe the question shouldn’t be so much what is “sufficient,” but how the
determination of “sufficiency” is in fact scientific. The question here is always some
variation of: If I use my judgment to determine sufficiency, then it is a somewhat
arbitrary and subjective decision and therefore inconsistent with the idea that friction
ridge identification is a science instead of an art. I do believe that friction ridge
identification is a science, not an art, but if I am going to testify to it, I have to be able to
explain it and counter those people who came before me who have characterized it as an
art. Cowger writes that T. Dickerson Cooke, one of the most respected workers in this
field, wrote in 1973 that, “Pronouncing that two friction skin impressions…were or were
not made by the same area of friction skin is an art, not an exact science. It is entirely a
matter of judgment based on training and experience (Cowger, 146-147).”
How can I counter that on the stand? Have I been led down the wrong path? My
confusion must be contagious and it may be spreading to the courts. More than one
defense attorney and more than one defense expert has attacked fingerprint evidence on
this basis alone. District Court Judge Michael had this to say in his dissenting opinion in
U.S. v. Crisp:
“One forensic expert (Stoney) contends that there
are no standards; there are no minimum point
requirements. The movement away from point
requirements ‘is not based on scientific study.
(Epstein)’ and there is disparity in the field
regarding the use of level 3 detail for id. (because of
distortion) ‘One dissimilarity’ in two impressions is
thought to be a universal standard, but if an
examiner believes the prints match they explain
away the difference rather than discounting the
match. Verification is considered to be essential, but
cases exist where no verification took place; and
even verification that does take place is not
independent and objective. All of this leads (Stoney
and Cole) to the belief that ‘[t]he criteria for
absolute identification in fingerprint work are
subjective and ill-defined.’ (Wertheim/Weekly
Detail 123)”
Judge Michael was not convinced that friction ridge identification is a science under the
rules of the court. Although the previous excerpt was from a dissenting opinion, Judge
Michael obviously feels strongly that the friction ridge identification field has not made
its case and he is in a position to influence decisions in similar cases. Perhaps James
Cowger was a little overly optimistic when he wrote, “that this element of judgment
exists as a necessary element of the comparison is certainly not seriously questioned
(Cowger, 148).”
I could find no explanation of how this judgment is not subjective or how this
subjectivity relates to friction skin identification being a true science in any of the
professional friction skin comparison sources. So I took it a few steps outside the
fingerprint realm to find my answers. First, I looked up the terms “subjective” and
“objective.” All of the dictionaries I looked at basically broke down the differences as
being dependent on personal feelings (subjective) or being independent of personal
feelings (objective). Fair enough. Then I looked into what makes any study a science.
The most consistent litmus test seemed to be the application of the scientific method. On
to looking up what exactly constitutes the scientific method. Guess what? Scientific
method does not include objectivity by definition in any reputable source I could find.
To me, this couldn’t be a mere coincidence, but it took a little more thought to fully
understand.
It finally hit me: Scientists in every field do use their judgment when they are
applying scientific method and principles. Take medicine for instance: Doctors use their
judgment every day, yet they are still simultaneously applying scientific methods and
principles. And just because they do so does not make medicine an art or even any less
of a science. What a concept. The judgment of a doctor is based on his or her training
and experience and this is why it is not purely subjective and this is why medicine is a
science even with the application of judgment. That is also why different friction skin
examiners can both look at the same print and come up with differing amounts that they
consider “sufficient.” The difference is because of the differences in training and
experience, not because the science is invalid. That simple. The problem? The texts in
this field do not explain it so simply.
Mark Beck helped me to understand subjectivity versus objectivity and
“sufficiency” with a very simple story. This is as good a time as any to share that story
with you:
A car runs a red light at a high rate of speed causing a fatal
accident. The car speeds away from the scene.
There are four witnesses to the entire incident. All four
were standing on the same street corner, the same distance from
the accident.
The first witness is a 16-year-old high school football
player. He tells the responding officer that the run vehicle was an
“old, shiny red and white convertible.” He doesn’t know a Chevy
from a Ford, knows even less about vehicle years, he doesn’t know
about different license plates and he did not pay attention to this
one anyway.
The second witness is an average 32-year-old male. He
reports to the officer that the run vehicle was an older model
Corvette convertible, red over white and that the vehicle had
Wyoming plates, but he did not get the number.
The third witness works at a Chevy dealership and is an
antique car buff. He tells the cop that the vehicle was a cherry red
over white 1958 Corvette convertible with Wyoming plates. He
further advised that he has attended antique car shows in the Rocky
Mountain Region for over 30 years and that he has only ever seen
one vehicle like that and he knows the owner’s name is John Smith
and that he lives somewhere in Laramie, Wyoming.
The fourth witness is an off-duty Wyoming State Patrol
officer. She tells the responding officer that the run vehicle was a
cherry red over white 1958 Corvette convertible with Wyoming
plates. She also advised that she had recently checked Department
of Motor Vehicle records for a similar vehicle that was involved in
a separate traffic incident she was currently investigating. Her
investigation to date in the other case revealed that there was only
one vehicle of this make, model, year and color registered in
Wyoming and that this vehicle was registered to John Smith of 123
Chestnut Ave. in Laramie, Wyoming.
All four witnesses saw the same thing from the same vantage
point. All four therefore had the same objective observation (facts
is facts). All four witnesses had the visual information available to
them to identify the run car, but only two of the witnesses had the
training and experience to individualize the vehicle.
This story did more to enhance my understanding of the whole subjectivity and
sufficiency argument than anything I have read or heard to date. It is a very simple way
to explain what I thought was a difficult concept. Maybe whoever writes the next friction
ridge comparison “Bible” would put in some easy examples like this for the dummies like
me?
This field went from a “counting points” standard to a “there is no scientific basis
for a minimum number of points” standard with little debate or explanation as to the
practical applications of this change. The practical result has been that too many
examiners of the day could not articulate the reasons behind the change and ended up
counting their points while telling everyone else that point counting is passé. Then these
examiners taught the new examiners and one of those new examiners was me.
More has changed in this field than just the way we count or don’t count
characteristics. The very explanation of how a comparison is conducted has changed.
But the literature on the subject is not written with readily understandable explanations in
mind. Most of the literature I have read does not explore friction skin comparison at the
lowest level, a level necessary to give every examiner a sound and consistent
understanding of the basics of friction skin identification. A “new basics” if you will. As
more challenges to friction ridge identification science are occurring regularly, the need
to address these issues should be paramount. The science needs to develop consistent
terminology and publish articles on the basics so we don’t have any more examiners like
me, who can make the identifications but not necessarily explain them. I am not the only
one with these experiences, but the chances of everyone else in this situation suddenly
having it all become clear to them, too, are slim to none. After all, where can they look
to get an explanation? As Ashbaugh so succinctly states the problem on the very first
page of his book, “While the ability to identify is inherent, an understanding of the
process and the ability to describe it is not.”
BIBLIOGRAPHY
Ashbaugh, D. (1999). Quantitative-Qualitative Friction Ridge Analysis: An Introduction
to Basic
and Advanced Ridgeology. Baca Raton, Florida: CRC Press.
Cowger, J. (1983). Friction Ridge Skin: Comparison and Identification of Fingerprints.
New York: Elsevier Science.
Field, A. (1959). Fingerprint Handbook. Springfield, Illinois: Charles C. Thomas.
Olsen, R. (1978). Scott’s Fingerprint Mechanics. Springfield, Illinois: Charles C.
Thomas.
Scientific Working Group for Friction Ridge Analysis, Study and Technology
(SWGFAST). (2002, August). Friction Ridge Examination Methodology for Latent Print
Examiners. 1. Retrieved January 19, 2004, from www.swgfast.org
Scientific Working Group for Friction Ridge Analysis, Study and Technology
(SWGFAST). (2002, August). Glossary – Identification. Retrieved January 19, 2004,
from www.swgfast.org
Wertheim, K. (2003, December). U.S. v. Crisp Dissenting Opinion. The Weekly Detail.
123. Retrieved December 15, 2003, from www.clpex.com