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🎯 Main Points

Expert Witness Testimony 👤⚖️

PSY513 - Forensic Psychology

🔑 Key Definitions

Expert Witness 👤: Someone with specialized knowledge, skill, experience, training, or education that qualifies them to offer opinions beyond common understanding
Frye Standard (1923) 📜: Scientific evidence must be "generally accepted" in scientific community
Daubert Standard (1993) ⚖️: Judge as "gatekeeper" - evaluates if testimony is testable, peer-reviewed, known error rate, generally accepted

📅 Important Dates

  • 1923 - Frye Standard established
  • 1993 - Daubert Standard established (US federal courts)

🎭 5 Roles of Forensic Psychologists in Court

  • 1. Competency evaluations - Fitness to stand trial
  • 2. Insanity evaluations - Mental state at time of offense
  • 3. Risk assessment - Future violence/dangerousness
  • 4. Child custody - Parental fitness, child needs
  • 5. Psychological injury - Emotional damages in civil cases

🏛️ Expert Witness Process (4 Steps)

  • 1. Receiving referral - Assess expertise match, conflicts of interest
  • 2. Case review & assessment - Records, interview, testing, collateral info
  • 3. Report writing - Clear, comprehensive, defensible
  • 4. Giving testimony - Deposition or live trial

⚖️ Daubert Criteria (4)

  • Can the theory be TESTED?
  • Has it been PEER-REVIEWED?
  • Known ERROR RATE?
  • GENERALLY ACCEPTED?

🎯 3 Prediction Approaches

  • Actuarial - Statistical algorithms, MORE accurate, may miss individual factors
  • Clinical - Professional judgment, flexible but MORE bias prone
  • Structured Professional Judgment - BEST of both!

⚖️ Ethical Considerations

  • Remain OBJECTIVE - not advocate for retaining party
  • Opinions based on DATA and SCIENCE
  • Acknowledge LIMITATIONS
  • Avoid dual roles (therapist shouldn't be expert witness for own patient)

💡 Exam Tips

  • Frye (1923) = "generally accepted" | Daubert (1993) = judge as gatekeeper
  • Daubert criteria: testable, peer-reviewed, error rate, acceptance
  • Structured Professional Judgment = best approach (combines actuarial + clinical)
  • Expert vs Ordinary witness: experts CAN offer opinions, ordinary CANNOT
  • Avoid advocacy - remain objective!
  • Cross-examination = opposing counsel tries to discredit