Skip to content

Patterson v. State, 146 A.3d 496 (Md. Ct. Spec. App. 2016)

Case (cite)
Patterson v. State, 146 A.3d 496 (Md. Ct. Spec. App. 2016)
Type of proceeding
Type of claim
Type of claim (second claim)
Expert evidence ruling reversing or affirming on appeal:
What was the ruling?
Correct to Admit
Type of evidence at issue:
Firearms identification
Defense or Prosecution Expert
Name of expert(s) who were the subject of the ruling
Joseph Williamson
Summary of reasons for ruling
Defendant argues that the court erred in allowing the expert to testify that the bullets were fired from his gun to the exlusion of all other guns in the world and denying his petition for a writ of actual innocence based on new evidence in the form of studies and literature showing the limitations of firearms identification. The court holds that firearms identification has been upheld by this court as recently as 2010 as satisfying the Frye-Reed Standard. The court says that if it is accepted in 2016, it "is inconceivable" that it would have led to a different result in defendant's 1993 trial and that the expert's testimony may have been limited but would not have been excluded.
The jurisdiction’s standard for expert admissibility at the time – list all that apply: (Frye), (Daubert), (Post-2000 Rule 702), (Other)
Second standard
Did lower court hold a hearing
Names of prosecution expert(s) two testified at hearing
Names of defense expert(s) who testified at hearing (or None).
Discussion of 2009 NAS Report (NAS2009)
Discussion of 2016 PCAST report (PCAST)
Discussion of error rates / reliability
Frye Ruling
Limiting testimony ruling
Language imposed by court to limit testimony
Ruling based in prior precedent / judicial notice
Daubert ruling emphasizing – which factors – (list 1-5)
Ruling on qualifications of expert
Ruling on 702(a) – the expert will help / assist the jury
Ruling on 702(b) – the testimony is based on sufficient facts or data
Ruling on 702(c) – the testimony is the product of reliable principles and methods
Ruling on 702(d) – reliable application of principles and methods to the facts of the case


“If it was not an abuse of discretion for a circuit court to conclude that an expert’s lies failed to overcome other compelling evidence of guilt, then it could not be an abuse of discretion to conclude, as the circuit court did in this case, that an expert’s undue emphasis on the certainty of his conclusions did not overcome the other compelling evidence of Patterson’s guilt, including the inculpatory testimony that the expert could properly have given”