Expert Witness

Definition of expert witness

An expert who helps the court understand issues outside its knowledge

Expert witness duties (Criminal Procedure Rules Part 19)

Be objective, unbiased, give opinion only within expertise, communicate clearly

Expert witness declaration

Duty to court overrides obligation to engaging party

Case Assessment and Interpretation (CAI)

Framework using competing propositions at source, activity, offence levels

Balanced view in forensic science

Scientists can address source and activity, not offence (guilt)

Prosecution vs defence involvement

Prosecution early (primary exams); defence later, often under time pressure

Contemporaneous notes

Accurate, unaltered, indelible ink, numbered, signed, securely stored

Report types SFR, Report, Abbreviated Statement, Full Statement

Short Format Report (SFR)

Brief summary, not for court, streamlines uncontested cases

Abbreviated Statement

Contains Section 9 CJA declaration, can be used in court

Full Statement

Detailed examination, conclusions, disclosure index, FER, Section 9 compliant

Expert witness in court

Provides opinion evidence, can observe trial, address court, sit with legal team

Risks of errors in court

Loss of reputation, evidence disregarded, career damage, possible prison