Proper Subject Matter (“Will Assist”)

1. Helpfulness. Expert testimony is admissible if it will assist the fact finder. There are two primary ways an expert’s testimony may assist.
   1. Complex Testimony. Experts can explain complex matters such as scientific evidence or extremely technical information that the fact finders could not understand without expert assistance.
   2. Unusual Applications. Experts can also help explain apparently ordinary evidence that may have unusual applications. Without the expert’s assistance, the fact finders may  misinterpret  the evidence.  See, United States v. Rivers, 49 M.J. 434 (1998); United States v. Brown, 49 M.J. 448
      (1998).
2. United States v. Traum, 60 M.J. 226 (2004). To answer the question of why a
   parent would kill her child, the government called a forensic pediatrician, who
   testified to the following matters: (1) overwhelmingly, the most likely person to
   kill a child would be his or her biological parent; (2) the most common cause of
   trauma death for children under four is child maltreatment; (3) for 80% of child
   abuse fatalities, there are no prior instances of reported abuse; (4) Caitlyn died of
   non-accidental asphyxiation. The CAAF held that there was no error in
   admitting “victim profile” evidence regarding the most common cause of trauma
   death in children under four and the fact that most child abuse deaths involve
   first-time abuse reports for that child. The CAAF held that the military judge
   erred in admitting evidence that overwhelmingly, the most likely person to kill a
   child is its biological parent. In context, however, the error was harmless
   because the government already had admitted the appellant’s confession.
3. United States v. Cendejas, 62 M.J. 334 (2006). Do you need expert testimony in
   a child pornography prosecution based upon the Child Pornography Prevention
   Act (CPPA), to prove actual children were used to produce the images? No. A
   factfinder can make a determination as to whether actual children were used to
   produce the images based upon a review of the images alone, without expert
   testimony. See also United States v. Wolford, 62 M.J. 418 (2006).

Borderline Personality Disorder & False Accusations in Military Sexual Assault Cases