Who writes your expert report? The Land and Environment Court of NSW’s new generative AI practice note and the decision in Wenkart v Blacktown City Council [2024] NSWLEC 117 makes plain that clear authorship of expert reports unaided by AI is crucial to the admissibility of expert reports.

Key points

• Gen AI must not be used to draft or prepare expert reports

• Parties may seek leave of the Court to rely on Gen AI to assist in analysing data when preparing expert reports

• The author of expert reports must be clearly identifiable by using the first-person pronoun.

Introduction

Expert evidence is a key part of proceedings in the Land and Environment Court of NSW. With the rise in generative artificial intelligence (Gen AI) software, the Court has a renewed focus on authorship of expert reports.

The Court’s new Gen AI Practice Notice sets out the rules for using Gen AI in expert reports. Whilst the decision in Wenkart v Blacktown City Council [2024] NSWLEC 117 illustrates the importance of clear authorship of expert reports for admissibility of reports and compliance with expert witness policies.

Generative AI and Expert Reports

On 21 November 2024, the Land and Environment Court of NSW issued Practice Note – Use of Generative Artificial Intelligence (Gen AI) (Practice Note) which provides rules and procedures for using Gen AI in expert reports. The Practice Note commences on 3 February 2025 and applies to all proceedings in the Land and Environment Court of NSW.

The Practice Notes defines generative AI (Gen AI) as “a form of artificial intelligence that is capable of creating new content, including text, images or sounds, based on patterns and data acquired from a body of training material”. This does not include technology which corrects spelling or grammar, provides transcription, assists with formatting and otherwise does not generate substantive content, or search engines.

Expert reports are required to state the opinion or opinions of the expert, and his or her reasoning process. As such, the Practice Note prohibits the use of Gen AI to draft or prepare the contents of an expert report used in legal proceedings.

However, parties may seek leave of the Court to use Gen AI for analysis in expert reports. For example, experts may use software that uses Gen AI to analyse sound, graphic or video data, or to interrogate very large data sets, or to conduct statistical analysis.

Applications for leave to rely on Gen AI must identify:

(a) the proposed use of Gen AI
(b) the Gen AI program (including the version) that will be used and whether it is a closed-source or open-source program or contains privacy and or confidentiality settings
(c) the benefit of using Gen AI in the preparation of the expert report
(d) any documents which it is proposed to submit to the Gen AI program for the purposes of generating any aspect of the expert report.

If the Court grants leave to use Gen AI, the expert preparing the report must:

(a) disclose in the report the sections prepared using Gen AI and the Gen AI program (and version) that was used
(b) keep records and identify in an annexure to the report a record of how the Gen AI tool or program was used
(c) if the use of Gen AI is regulated or addressed by any relevant code of practice or principles that bind or apply to the expert, identify that fact and annex to the report a copy of the relevant code(s) or principle(s).

If you are preparing an expert report for Court proceedings, you must ensure that Gen AI is not used to draft an expert report, and Gen AI cannot be used to analyse data without leave of the Court.

Authorship of Expert Reports

The authorship of an expert report was recently questioned in Wenkart v Blacktown City Council [2024] NSWLEC 117. This case concerned the admissibility of a valuation report prepared by the Applicant’s valuer for class 3 land valuation proceedings in the Land and Environment Court of NSW.

Council objected to the Applicant’s valuer’s expert report on the basis that the authorship of the report was unclear because of the use of the first-person collective pronoun “we” throughout the report. For example, the report included phrases such as “we understand”, “we have analysed”, “based on our analysis”.

The opinion rule in s 76 of the Evidence Act 1995 (NSW) does not apply if a person has specialised knowledge based on the person’s training, study or experience and the evidence of an opinion of that person is wholly or substantially based on that knowledge. The exception to the opinion rule applies to opinion of a single person.

Whilst the rules of evidence do not apply to class 3 proceedings, r 31.23(1) of the Uniform Civil Procedure Rules 2005 (NSW) provides that an expert witness must comply with the Expert Witness Code of Conduct which requires an expert witness to be a single expert. The opinion rule also provides guidance to the Court.

The Court accepted that the use of “we” in Applicant’s valuer’s report was ‘entirely opaque’ because the report did not identify another person who undertook investigations or whose opinion the valuer accepted whilst preparing the report.

To determine the use of “we” in the report, the Applicant’s valuer was called to give evidence about the use of “we” in the valuation report. That evidence made plain that the report was drafted by one person with assistance from others on research and analysis.

The Court held that “[d]espite […] considerable reservations concerning a serious non-compliance with the Expert Witness Code of Conduct in relation to critical matters of valuation evidence, in particular the identity of the author of the report on which the Applicants seek to rely […] in light of the evidence given on the voir dire and the fact that the rules of evidence do not apply in Class 3 proceedings” the report was admitted into evidence:[30]

Absent the further evidence of the Applicant’s valuer, the report was inadmissible due to non-compliance with the Expert Witness Code of Conduct.

To avoid the expense of adducing further evidence and to ensure compliance with expert witness policies and codes of conduct, it is, therefore, important to use the first-person pronoun when drafting an expert report.

Summary

When preparing expert reports for Court proceedings, it is important to make clear who the author is and to not use Gen AI to draft the report. Using Gen AI to analyse data without leave of the Court and poorly drafted reports which do not clearly identify whose opinion is expressed, impacts the admissibility of expert reports. To ensure the admissibility of expert reports, it is important to:

1. Not use Gen AI to draft or prepare a report
2. Seek leave of the Court if you would like to use Gen AI to analyse data or prepare a chronology for an expert report
3. Use the first-person pronoun when expressing opinions in expert reports.