Expert Witness Testimony Frye 1923: Relates to the admissibility of scientific evidence in court. Stresses OBJECTIVITY in forensic testimony Conclusion: Any scientific evidence presented in court MUST HAVE GAINED GENERAL ACCEPTANCE IN THE PARTICULAR FIELD IN WHICH IT BELONGS.

Expert Witness Testimony Federal Rules of Evidence 1975 Set of evidentiary rules for civil and criminal cases Rule 702 specifically addresses witness testimony: Witness qualifies as expert by knowledge, skill, experience, training, and education

Expert Witness testimony 1993 Daubert vs. Merrell Dow Pharmaceuticals Court determined standards for admitting EXPERT TESTIMONY in federal court

Expert Witness Testimony Court determined that Federal Rules of Evidence Overturned the Frye standards Standards: Should be SCIENTYIFICALLY valid, that is to say knowledge should be grounded in methods and procedures of science Should be RELEVANT, that is to say have a valid scientific connection to the pertinent inquiry (full moon) So the Daubert Test or Guidelines were produced

Daubert Guidelines 1) Content of forensic scientific testimony must be testable by scientific method 2) Opinion of expert must have been peer reviewed (published) 3) Association of established reliability and known error ranges 4) Requires that methods or opinions presented in scientific testimony have achieved general acceptance within the relevant scientific community

ESTIMATING SEX IN SKELETAL REMAINS

Sex is not gender Sexual dimorphism is a physical secondary sexual characteristic conferred by hormones on the maturing mammal; and is usually discrete physiologically and chromosomally Gender is a sexual identity chosen by an individual or conferred by society and marked by extra-somatic artifacts.

Determining sex of skeletal material Be aware that, typically, only 30% of missing persons are female. Also, determination of sex from intact, often clothed, skeletons is not usually too problematic. Osteologists usually determine only the biological sex of an individual, not gender which is a socially-acquired or conferred identity.

Beware personal bias in sex assignment to skeletal remains Most missing persons are male Most murder victims are male Healed nasal fractures are twice as common in males (but do occur distressingly often in females) Adolescent crania are difficult to sex and teenage male prostitutes do exist

Determination of Sex: essentials 1. Pelvic girdle and especially pubic area (Phenice’s criteria) are best (>95%) 2. Skull form is pretty reliable (but beware masculine looking females in forensic work) Long bone metrics are also fairly reliable Amelogenin = protein found in developing tooth enamel.

Categories of Sex Assessment

Determining Sex from Crania Daubert acceptable

Supraorbital Torus / Glabella Male Female

Supraorbital Margins FEMALES: sharp MALES: rounded

Mastoid Process Female Male

Nuchal Line Development Male

Chin Shape Male - bilobate Female - prominent

Determining Sex from Innominates

Phenice’s criteria are considered the most reliable sex markers

Ventral Arch Male Female

Ischiopubic Ramus Female Male

Subpubic Concavity Female Male

Preauricular Sulcus Present in females Absent in males

Length of the Pubic Bone Male Female

Sciatic Notch Not too reliable: 75% Female

Acetabular Size Correlates to Size of femoral head Cannot use strict translation Of max. femoral head standards Usually larger in males and differ in males due to body size and weight bearing. male

Sexing a Sacrum male female

Determining Sex Metrically Vertical Femoral Head Diameter Females: <41.5 mm Females (?): 41-5 to 43.5 mm Ambiguous: 43.5 to 44.5 mm Males (?): 44.5 to 45.5 mm Males: >45.5 mm

Vertical Diameter Humeral head Female: <43 mm Ambiguous: 43 a 47 mm Masculine: >47 mm

In extremis There are dozens of osteometric techniques for sex determination Typically, they successfully assign unknowns correctly 80-90% of the time.