Guide
What an expert witness report must contain
A medical expert’s report is written for the court, not for the party paying for it. That single fact decides its contents, its tone and the statements it has to carry at the end.

The starting point
The duty is owed to the court
Under CPR Part 35 an expert’s duty is to help the court on matters within their expertise, and that duty overrides any obligation to the party instructing or paying them. Everything else in this guide follows from it: the report has to disclose the range of opinion, not just the convenient end of it, and it has to show the reader how the conclusion was reached.
Part 35 and its Practice Direction govern proceedings in England and Wales. Scotland and Northern Ireland have their own rules and their own expectations of expert evidence, so a report prepared for one jurisdiction should not be assumed to satisfy another.
Contents
What the Practice Direction requires
Practice Direction 35 sets out what a report must contain. In practice these are the sections a reader looks for, in the order they expect to find them.
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Qualifications
Details of the expert’s qualifications, stated at a level that lets the court judge whether the opinion falls within their expertise.
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Literature and material relied on
The literature or other material the expert has drawn on in making the report.
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The substance of the instructions
A statement setting out the substance of all material instructions, written or oral, on which the report is based.
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Who did the work
Where tests or examinations have been used, who carried them out, under whose supervision, and their qualifications.
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The range of opinion
Where there is a range of opinion on the matters dealt with, a summary of that range and the reasons for the expert’s own view.
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A summary of conclusions
The conclusions, gathered in one place, so they can be read without reconstructing them from the body of the report.
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The statement of duty
A statement that the expert understands and has complied with their duty to the court.
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The statement of truth
The statement of truth in the form the Practice Direction prescribes, confirming the opinion is the expert’s own and that they have made clear which facts are within their own knowledge.
In practice
Where reports come unstuck
Opinion beyond the discipline
A report that strays outside the expert’s field invites the question of who is qualified to give that part of the evidence. Where a claim spans more than one discipline, that usually means more than one expert.
Instructions left unstated
The substance of material instructions has to appear in the report. Summarising them thinly is a common source of questions later.
A range of opinion left out
Where responsible practitioners disagree, saying so and explaining the choice is stronger than presenting one view as settled.
Assuming one set of rules
A report drafted to Part 35 is drafted for England and Wales. Instructions in Scotland or Northern Ireland are governed by their own procedure.