Handling new evidence
How to deal with new evidence that alters your opinion
An expert recently contacted the Register Helpline to say that he was due to give evidence in a case and had come across a published document, dated the year before his report, which gives new data that had a bearing on one of his opinions. He was off to tell the solicitor, but wondered what the Court might expect him to do and how.
This was a civil case, so one should first turn to the Civil Procedure Rules (CPR). The guidance (see http://www.jspubs.com/experts/library/lib_g4e.cfm) annexed to CPR Rule 35 states at para 14:
14. Experts should inform those instructing them without delay of any change in their opinions on any material matter and the reasons for this (see also paragraphs 64-66).
and at 64-66:
Amendment of reports
64. It may become necessary for experts to amend their reports:
- as a result of an exchange of questions and answers;
- following agreements reached at meetings between experts; or
- where further evidence or documentation is disclosed.
65. Experts should not be asked to amend, expand or alter any parts of reports in a manner which distorts their true opinion, but may be invited to do so to ensure accuracy, clarity, internal consistency, completeness and relevance to the issues. Although experts should generally follow the recommendations of solicitors with regard to the form of reports, they should form their own independent views on the opinions and contents of their reports and not include any suggestions that do not accord with their views.
66. Where experts change their opinion following a meeting of experts, a signed and dated note to that effect is generally sufficient. Where experts significantly alter their opinion, as a result of new evidence or for any other reason, they must inform those who instruct them and amend their reports explaining the reasons. Those instructing experts should inform other parties as soon as possible of any change of opinion.
That makes it all quite clear. All the court requires of experts in these circumstances is that they inform those who instruct them without delay.