Expert's Overriding Duty
Definition
The principle, codified in CPR Part 35.3 and equivalent rules, that an expert witness's primary obligation is to assist the court rather than to advance the interests of the retaining party. It overrides any contractual duty to the client.
- Codification
- CPR Part 35.3 and equivalent rules in other jurisdictions
- Core rule
- Primary obligation runs to the court, not the retaining party
- Overrides
- Any contractual duty owed to the paying client
- Applies to
- Both court-appointed and party-instructed experts
Common questions
Is this the same rule as the general expert duty to the court?+
Yes, it is the same underlying principle restated under different terminology. Different jurisdictions and rule sets codify the identical idea, that an expert's overriding obligation runs to the court rather than to whoever pays the fee.
What practical step in a report demonstrates that an expert has honoured this duty?+
The report should disclose the facts and assumptions relied on, the reasoning connecting them to the conclusion, and any range of opinion within the field, so a reader can see the opinion was reached independently rather than shaped to fit the instructing party's case.
Related terms
- Concurrent Evidence (Hot-Tubbing)
- A procedure used in some common-law jurisdictions, particularly in Australia and international arbitration, where opposing experts are examined simultaneously by the tribunal...
- CPR Part 35
- The Civil Procedure Rules section governing expert evidence in England and Wales. It establishes the expert's overriding duty to the court, the...
- Daubert Standard
- The US federal evidentiary standard (Daubert v. Merrell Dow Pharmaceuticals, 1993) requiring that expert testimony be based on scientifically valid methods with...
- Frye Standard
- The US legal test for admissibility of scientific evidence, originating from Frye v. United States (1923), which required that a technique be...
- Section 45 (Indian Evidence Act)
- The provision of the Indian Evidence Act 1872 that permits courts to consider the opinions of persons with special skill in science...