How to write an expert witness report in Australia

A well-written expert witness report does two things at once: it withstands cross-examination on the technical merits, and it reads clearly enough for a judge or tribunal member without a technical background. Everything below assumes an Australian civil context — construction, engineering, remedial and strata matters — and assumes the expert has already agreed to be bound by the applicable Expert Witness Code of Conduct.

The structure Australian courts expect

• Cover and identification. Report title, matter reference, date, expert's name and firm.
• Instructions. Verbatim reproduction of the letter of instruction and the questions posed.
• Acknowledgement of the Code. A clear statement that the expert has read and agrees to be bound by the applicable Code.
• Qualifications. Relevant qualifications, registration, experience and prior expert engagements.
• Assumed facts and materials. The documents reviewed, inspections conducted, tests performed and the factual assumptions relied on.
• Analysis and reasoning. The technical assessment — separated question by question.
• Opinions. Each opinion clearly identified, with a plain-language summary.
• Declarations. Any qualifications, limitations, or matters that would alter the opinion.
• Appendices. CV, list of documents reviewed, photographs, test results, calculations, drawings.

Writing style — what the court actually wants to read

• Short sentences. One idea per sentence.
• Plain English first, technical terminology second and always defined.
• Numbered paragraphs, numbered questions, numbered opinions — everything cross-referenceable.
• Photographs captioned with location, date and what the reader is being asked to see.
• No advocacy adjectives. Let the reasoning carry the weight.

The reasoning chain — the single most tested part of any report

Cross-examination almost always targets the link between an assumption, the technical analysis and the opinion. If the reader cannot trace how the expert moved from what was observed to what was concluded, the opinion will be discounted. A clean reasoning chain looks like:

• Observation. What was seen, measured or tested.
• Standard or reference. The applicable Australian Standard, code, manufacturer specification or accepted engineering practice.
• Comparison. How the observation departs from that standard.
• Cause. The most probable cause identified from that departure, with alternative causes considered and excluded.
• Consequence. The impact on serviceability, safety, durability or scope of rectification.

Handling contested facts

Where facts are disputed the expert should present opinions on both hypotheses rather than picking one. A report that says if assumption A is preferred my opinion is X; if assumption B is preferred my opinion is Y is far more useful to the court than one that quietly adopts a preferred version of events.

Scott Schedules and joint expert reports

In construction litigation the individual expert report is often accompanied by a Scott Schedule — a tabular schedule of every defect with columns for description, location, cause, scope and quantum. Where the court orders a joint experts' conclave the eventual joint report should record areas of agreement, areas of disagreement, and the reasons for each remaining disagreement.

Common report failures

• Opinions that go beyond the questions asked.
• Opinions expressed without stating the assumed facts.
• Missing acknowledgement of the Code.
• Photographs without captions or scale.
• Calculations without inputs, references or working shown.
• Undisclosed prior involvement with a party, site or design.