Fingerprint Competency
Written by Michele Triplett   

IT IS ALWAYS IMPORTANT for latent-print examiners to show that they are proficient and competent at their jobs. To do this, some examiners rely on their years of experience, while others point to the accreditation of their laboratory. A number of examiners earn certification by the International Association for Identification (IAI). And still others take proficiency tests on an annual basis.
With regard to proficiency testing for a latent-print examiner, for years there has been only a single company that provided such testing services: Collaborative Testing Services (CTS). If a person or an agency wanted a different type or level of testing, the only option was to make up their own test.

Today, there is another option avail-able. Competency Assessment Services Limited (CAS Ltd.) provides latent-print proficiency-testing services to the forensic community. The company is based in Essex, England but has representatives who are located in the U.S.

Before going further with this review, I should point out that I have no affiliation with CAS Ltd. My interests in this matter are limited to reporting the benefits and shortcomings of what is available to our discipline.

Since 2001, I have participated in the proficiency testing offered by CTS, but I have always wanted more out of a proficiency test. Specifically, there are three things that are of interest to me: 1) testing latent-print examiners for their ability to make exclusions rather than just individualizations; 2) asking latent-print examiners for justification to support conclusions; and 3) asking latent-print examiners to state the scientific principles that were used to arrive at a conclusion.

Some latent-print examiners feel that while CTS does test the ability to exclude different suspects, the term they use—NI for Not Identified—can be confusing. It is confusing because some people take this term to mean exclusion, while others think it indicates that they could not find the exemplar that left the latent print. And then there are others who use NI to indicate that consistency exists but not sufficiency. Regardless of the company’s intent, this is an area that could be clarified and tested.

The search for a new latent-print proficiency test

In 2006, I was intrigued when another proficiency-testing firm—Quality Forensics—advertised that they would have a new latent-print test available in early 2007. I do not know the details, but apparently the company never did go forward with offering a new proficiency test to latent-print examiners.

Later in 2006, I heard about CAS Ltd. and their proficiency test. I immediately contacted them to see how their test was going to differ from what was already available. I was pleased to get a response from them right way. They told me that their test would test individuals, would have quality materials, would be made with ground-truth conclusions, would be proctored independently, and would be timed. Only latent-print examiners are allowed to take this test. They said they were hoping to have their testing academically accredited, as well as sanctioned by ASCLD/LAB. These points were important to me since other tests can be taken by an individual or taken as a group by an entire lab. Such tests are typically proctored by the agency taking the test, so they may not represent the proficiency of individual examiners.

I decided that taking the CAS Ltd. test would tell me what I needed to know. In early January of 2008, CAS Ltd. coordinated the details with Lloyd Thomas from the Seattle (Washington) Police Department, an agency near my own. They mailed Thomas the test and he generously agreed to oversee the testing process. He arrived in my office the morning of February 8, 2008. The test was still sealed, so we opened it and began the testing process. The materials were of the highest quality. As a matter of fact, the quality was so good that the exemplars looked just like inked prints. This was very different from what I was accustomed to. The CTS test, for example, provides color photographs of black and white latent prints and exemplars. The result is a color distortion that leaves a yellowing on all of the test materials. While this never really interfered with my ability to complete a CTS test, I was able to notice the difference between the two sets of materials.

First-hand experience: Actually taking the proficiency test

The CAS Ltd. test was three hours long and the directions indicated that I could use a comparator. I did not use one, however, as I have never used or even seen a comparator, and do not have access to one. My office enlarges and enhances images using Adobe Photo-shop that serves a similar purpose. Since this was not mentioned in the directions for the CAS Ltd. test, I just used my 4.5x magnifiers.

I should mention that I became an LPE in 1998, finished my training in the end of 1999, and became certified in 2003. I am not one of those amazing examiners who can individualize the smallest distorted latent print in a matter of minutes. Sometimes I get lucky, but for the most part I consider myself to be an “average” examiner. I also tend to be anxious by nature, so I am not fond of timed tests.

The three hours allotted for taking the test included the time I had to spend reading the directions. This, of course, would eat into my comparison time. I began to regret having been so inquisitive about this test.

The actual test material included 12 latent prints and six sets of exemplars. I could not find the first two latent prints I looked for. About 45 minutes had passed and I hadn’t identified a single print. This was not looking good! I recalled a few of the little tricks and techniques that Ron Smith of Ron Smith and Associates, Inc. had taught me during some of my earlier training
—and the next latent print I picked up was quickly identified to the first person I looked at.

Part of my anxiety was caused by the structure of a test that I was not familiar with. If I were to take this test again, I am sure that I would feel much more comfortable. I am not making excuses for my results, because I am satisfied with how I did on the test. I was able to identify eight of the twelve latent prints and excluded the exemplars from leaving one latent print. I was hesitant about excluding the others without getting a good night’s sleep and double-checking my conclusions the next day—which is something that I sometimes do in my actual case work.

Comments about the CAS Ltd. proficiency test

As I said earlier, the quality of the test materials was excellent. The difficulty level of the test was perfect, in my opinion. Perhaps it was a little harder than typical casework, but it offered a level of difficulty that is needed by latent-print examiners.

The test reminded me of the IAI Certification Test. It had a good combination of latent prints from different parts of the hands. Another thing I liked was the fact that the test was arranged so the examiner had to look at the rolled impressions, the flats, and the palm prints because many of the latent prints could not be individualized to the rolled impression. In order to achieve a passing score on the test, it is necessary to get eight correct conclusions of either individualization or exclusion.

The cost of the proficiency test offered by CAS Ltd. was $275, which was just slightly less than the cost of the CTS test.
I would highly recommend the CAS Ltd. test as a way to show the competence of any latent-print examiner.

Even if agencies do not require such a test, this is an excellent way for examiners to demonstrate their competence. One of the best aspects is that it has the difficulty level of the IAI Certification Test but is available to examiners who do not have the experience required to take that test. Using the CAS Ltd. test should also be a legitimate way to determine the abilities of potential examiners during the hiring process.

In my opinion, the independent proctoring offers the objectivity that is essential in a scientific profession.

Suggestions about how to improve proficiency testing

One element of testing that I am still trying to promote to all agencies and testing companies is that they should require justification of conclusions. My personal feeling is that this should be essential because the foundation of the scientific conclusions is in the justification. Since this is a vital part of science, proficiency and competency should take both the conclusion and the justification into account. The CAS Ltd. test comes with a very professional workbook that has room for justification—but justification is not required at this time. I also wonder how a conclusion would be scored if someone recognized the consistency between a latent and the exemplar but they did not individualize it due to their own sufficiency requirements.

Just ten days after I took the CAS Ltd. test, I received a comprehensive report with my test results. There were two things in the report that surprised me. First, I was surprised that that my test results had come back so quickly. And second, I was surprised that the written test results went far beyond merely indicating that I had received a passing grade.

The report actually commented on the notes that I had made in my test book. Most of my comments were just notes that I was making to myself—as I do in normal casework—and I had no reason to think that someone would go to the trouble of replying to them.

For instance, when I’m working a case with multiple latent prints, my first step is to do a preliminary assessment of the latent prints. I might indicate if the latent print is a whorl, a tip, a palm, or an impression that I don’t have a clue where to search. I also indicate the quality and the quantity of information with comments such as …it’s very light and hard to visualize. Or I might write …there’s very little second-level detail but it’s very clear.

During the CAS Ltd. test, I made numerous written comments such as this as a way to categorize the latent prints so that I could compare the easiest latent prints first. That is why I was somewhat surprised when I saw that my comments were addressed by the person who corrected my test. If I had known someone would be analyzing my comments, I would have indicated why I was writing those notes.

For example: When I noted that a latent print had very little second-level detail, I was indicating that it would take longer to correctly orient and locate that image. I was not indicating that I thought a particular latent print did not have enough quantity for individualization. Perhaps I could have stated it better. As our discipline moves toward better documentation, I am sure we will all get better at articulating the meaning behind our thoughts.

Background information about the proficiency-test resource:

After I took this test, I did some background checking and learned some more about CAS Ltd., the company that offers the proficiency test:

  • Their latent-print test is endorsed by London South Bank University.
  • They are currently in the process of designing an extension to their com-parison test that will include questions on latent-print history, law, and chemical development.
  • They are also in the process of designing a tenprint competency test. If anyone would like to express their thoughts on what should be included on a tenprint competency test, I suggest they contact CAS Ltd. directly.

And if you would like to get more information on the company and the tests they provide, you can visit their website at this address:

About the Author:

Michele Triplett is the Latent Print Supervisor of the King County Sheriff’s Office in Seattle, Washington. She holds a Bachelor of Science degree in Mathe-matics and Statistical Analysis from Washington State University. She has worked in the friction-ridge identification discipline for more than 13 years. Triplett currently serves on the Editorial Review Board for the Inter-national Association for Identification (IAI) and is a member of the IAI General Forensics Subcommittee.


 "Fingerprint Competency," written by Michele Triplett
March-April 2008 (Volume 6, Number 2)
Evidence Technology Magazine
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