Expert Blog

Can Lawyers Change Expert Witness Reports?

changing report

The question being considered today is to what extent can solicitors and/or barristers edit the report of an expert witness, sometimes known as ‘settling’ an expert’s report. The basis for this question arises from several conflicting duties that the law requires of both witnesses and lawyers. On the one hand, lawyers and witnesses owe a duty to the court.[1] Specifically, expert witnesses are to give their opinion independently and impartially.[2] On the other hand, the law aims to reach the ‘just, quick and cheap resolution of the real issues in the proceedings.’[3]

With respect of the duties to the court, it is clear that experts are not merely ‘hired guns’. One example of the courts looking down upon this behaviour is an English case, Vernon v Bosley (No 2). In this case the solicitor for one party wrote a letter to their expert after receiving their draft report which included phrases such as:

  • “We need to show that…”;
  • “… we need to establish that…”; and
  • “… we will need to convince the judge not to…”[4].

Lord Justice Thorpe’s response to this letter was:

This sort of attempt to influence the expression of expert opinion is to be deplored for the simple reason that it colludes in a partisan approach and ignores the expert’s duty in Children Act proceedings to write every report as though his instructions came from the guardian ad litem.

The influence that this instruction had upon Mr. Mackay’s report is obvious.[5]

The contrasting line of reasoning was expressed succinctly by Justice Lindgren in Harrington-Smith:

My impression is that in some cases, beyond the writing of an initial letter of instructions to the expert, lawyers have left the task of writing the reports entirely to the expert, even though he or she cannot reasonably be expected to understand the applicable evidentiary requirements. Such a course may have been followed because of a commendable desire to avoid any possibility of suggestion of improper influence on the author. But I suggest that the distinction between permissible guidance as to form and as to the requirements of ss 56 and 79 of the Evidence Act, on the one hand, and impermissible influence as to the content of a report on the other hand, is not too difficult to observe.[6]

The last phrase is incredibly important. Whilst it is hard to describe and discern, there is clearly a line between assisting witnesses and impinging upon their independence. In the first case it is clear that the lawyer was describing what factual findings the expert needed to (and therefore, should) come to in order to support their client’s claim – which clearly crossed the line.

This is not the only valuable advice that Lindgren J gives in Harrington-Smith. He goes on to note that lawyers should be involved in the report writing process and in doing so, he sets down one of the most fundamental rules of expert witness reports:

Lawyers should be involved in the writing of reports by experts: not, of course, in relation to the substance of the reports (in particular, in arriving at the opinions to be expressed); but in relation to their form, in order to ensure that the legal tests of admissibility are addressed.  In the same vein, it is not the law that admissibility is attracted by nothing more than the writing of a report in accordance with the conventions of an expert’s particular field of scholarship.  So long as the Court, in hearing and determining applications such as the present one, is bound by the rules of evidence, as the Parliament has stipulated in subs 82(1) of the NT Act, the requirements of s 79 (and of s 56 as to relevance) of the Evidence Act are determinative in relation to the admissibility of expert opinion evidence.

Conversely, overseas courts have been known to take a much stricter approach than this. The decision of Moore v Getahun 2004 ONSC 237 demonstrated the Canadian Court’s position on the matter. In this medical negligence case, it was discovered in the course of evidence that counsel for the defence had made some ‘suggestions’ and ‘corrections’ during a phone conversation, and these ‘suggestions’ and ‘corrections’ were then included in the final report. This was deemed a breach of the Ontario Rules of Civil Procedure, and as such, the judge found that:

The expert’s primary duty is to the court… I conclude that counsel’s practice of reviewing draft reports should stop. There should be full disclosure in writing of any changes to an expert’s final report as a result of counsel’s corrections, suggestions, or clarifications, to ensure transparency in the process and to ensure that the expert witness is neutral.

In Australia, we are yet to see High Court authority on the issue, however, given case law thus far, it is unlikely that any and all amendments/suggestions by lawyers will detract from an expert’s credibility, or leave the lawyer/witness in breach of their duties (which could result in being held in contempt!). Nonetheless, it is important for experts and lawyers to be aware that if their conduct does cross the line, it will be extremely damaging for their case, and their reputations.

This article was prepared in conjunction with Truman Biro.


[1] See, eg, Civil Procedure Act 2005 (NSW), s 56; Supreme Court of NSW Expert Witness Code of Conduct: Uniform Civil Procedure Rules 2005 (NSW), Schedule 7.

[2] See, eg, Supreme Court of NSW Expert Witness Code of Conduct: Uniform Civil Procedure Rules 2005 (NSW), Schedule 7.

[3] See, eg, Civil Procedure Act 2005 (NSW), s 56.

[4] [1999] 1 QB 18, 58.

[5] Ibid.

[6] Harrington-Smith on behalf of the Wongatha People v State of Western Australia (No  2) (2003) 130 FCR 424, 429 [27].


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