Making Optimal Exclusion and Identification Latent Print Decisions

Making Optimal Exclusion and Identification Latent Print Decisions


 

Course Outline:

Times are subject to change throughout this workshop depending on student participation, exercise timings, with two 15-minute breaks in the morning and two15-minute breaks in the afternoon with a one-hour lunch about noon.

Day 1
0800-0815
Introductions and Administration
Instructor introduction, overview of lectures, exercises, answer sheets
0815~1600 Lecture topics:

  • Forensic Comparative Science
  • Introduction to Philosophy of Knowing and Believing
  • Introduction to Cognitive Psychology, Vision Science, Knowing and Believing
  • Uniqueness and Persistency of the Features of the Source
  • Examination Process
  • AACE+V: Analyses, Analyses, Comparisons, Evaluations, plus Verification
  • Levels of Details of Features of the Skin
  • Tolerance, Variation of Appearance, No Perfect Matches
  • Qualitative Quantitative Sufficiency
  • Conclusions: Exclusion, Inconclusive, and Identification
  • SWGFAST Documents related to the examination process
  • Excluding the Source, the Finger, the Hand, or the Person
  • Selected articles on the Exclusion Decision
1600-1700 Introduction to Practical Exercises:
Hands-on detailed introduction to the exercises will be given. Students will use multi-color highlighters to mark details in impressions, and mark the answer sheet with the selected conclusions. The instructor will tabulate these answers and review the ranges of conclusions while presenting and discussing the impressions under consideration.
Day Two
0800-1700
Practical Exercises:
15-minute review of lectures, previous day, and current day preview. Practical exercises, current tabulation of conclusions, presentations of conclusions, and discussions of conclusions while reviewing impressions on the video screen.
Day Three
0800-1700
15-minute review of lectures, previous days, and current day preview. Practical exercises, current tabulation of conclusions, presentations of conclusions, and discussions of conclusions while reviewing impressions on the video screen.
Day Four
0800-1500
15-minute review of lectures, previous days, and current day preview. Practical exercises, current tabulation of conclusions, presentations of conclusions, and discussions of conclusions while reviewing impressions on the video screen.
1500-1630 Overall tabulation of conclusions, presentation of overall conclusions, discussion of conclusions, discussion of ‘Exclusion-Inconclusive-Identification’ versus ‘Exclusion-Ranges of Inconclusives-Identification’ conclusions.
1630-1700 Administrative reviews. Presentation of certificates.

 

Course Duration

4-days, 32 hours, 8:00am until 5:00pm (or # days, # of desired hours)

 

Course Description

Participating students will be provided a variety of lectures and discussions to build a foundation for expert decision-making in latent print examinations.
Participants will be provided enlarged friction skin impression images for examinations with the goal to improve their perceptual and decision making abilities. Using known-source images, computer visual noise was previously added to many of the images without altering the actual details within the friction skin impressions. Examiners normally select from the three conclusions of exclusion, inconclusive, or identification in their casework. In this training,
participants will be allowed to select from a range of conclusions within the ‘inconclusive’ decision without using the ‘neutral inconclusive.’ The reason for this is to allow the participants to fine-tune their decision-making while using instructor known ground truth source impressions. Conclusions will be tabulated and provided within the workshop so participants can consider whether their sufficiency thresholds could be adjusted within self and in relation to
their peers while still correctly excluding or identifying impressions without relying too much on the inconclusive decision, yet not abandoning the inconclusive decision. This training course will present a series of interactive lectures using PowerPoint. The instructor will provide an overview of the examination process and conclusions with lectures and hands-on exercises using enlarged images of friction skin impressions, which have known ground truth source(s) of origin. There will be various lectures, discussions, exercises, and student discussions related to the latent print examination process and conclusions that are reached. Numerous exercises will be provided. Shortly after completion of small groups of exercises, the aggregate total of the students’ conclusions will be discussed.

Course Objectives:

Excluding the source of a latent print can be very difficult. In this workshop, participants will work through a variety of enlarged friction skin impression
comparisons to improve their perceptual and decision making abilities in latent print examinations. As part of their jobs, examiners must construct a threshold of sufficiency within self and in relation to their peers for what constitutes an exclusion or identification decision. As examiners improve their abilities, these thresholds will need to be updated. Exercises in this workshop will help the participants develop a principled technique to discover where the thresholds need to be within self and among peers for exclusion and identification decisions, without being wrong, or concluding inconclusive, to match their current and improving abilities.

Dress Code:

Dress code for this training is in accordance with your laboratory policy. Business casual clothing is suggested.

Cell Phone:

As your instructor I have no issues with cell phones. However, if your phone vibrates please answer it outside of the classroom. Please do not text during class.

Course Training Material:

A copy of the PowerPoint lectures, enlarged images of friction skin impressions for the comparative examination exercises, highlighters for marking details in the images, and answer sheets will be provided by the instructor.

Suggested Prior Reading:

The Fingerprint Sourcebook, Examination Process chapter 9, NIJ,
https://www.ncjrs.gov/pdffiles1/nij/225320.pdf
Forensic Comparative Science – Qualitative Quantitative Source Determination of Unique Impressions, Images, and Objects. John R. Vanderkolk, Academic Press/Elsevier, 2009.

Instructional Methods:

The following instructional methods are incorporated into this course:

  • Independent student readings prior to course
  • Lecture presentation
  • Practical exercises
  • Discussion
  • Self-assessment within the group of peers

 

Course Structure/Approach :

A variety of approaches will be used in instructing course material. Some of the approaches that will be used are listed below:

  • Independent examination of impressions
  • Review of each comparative exercise
  • Presentation of the aggregate of students’ determinations for each comparison
  • Presentation of the aggregate of students’ determinations for all comparisons
  • Personal determination of whether the student’s threshold could be adjusted between the exclusion/inconclusive decision or the inconclusive/identification decision throughout and at the end of the workshop.

 

Required Equipment:

Projector and screen are to be provided by the host. The instructor will provide all handouts, exercises, and markers.

Course Participation:

Students should consistently contribute to class discussions and activities. During the comparison exercises, students will work independently. Shortly after
completion of a small group of exercises, the conclusions will be tabulated and then the impressions will be displayed and discussed. Students will learn where their conclusions are in relation to their peers and whether an exclusion or identification decision is warranted over an inconclusive decision.

Suggested readings:

Students are encouraged to accomplish the readings listed under the Reading section. This will better prepare us for our interactive discussions.

Practical Exercises:

Approximately three quarters of the workshop will be the active accomplishment and discussions of practical exercises during this training.