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Instructing an Expert Witness

What needs to be included

Instructions should be:

  1. In writing
  2. Clear and concise
  3. Specify exactly what you want the Expert Witness to do – consultant/advisor or court Expert Witness?
  4. Specify exactly what will be available to them in terms of evidence
  5. Specify exactly the questions you want them to answer
  6. Identify any relevant standard of proof to which the Expert Witness must work or any relevant governing case law

The instruction letter

The letter will need to:

  • Set out the factual matrix
  • Individually list what documents you are providing, ideally in a paginated and indexed bundle, especially when dealing with any large volume of material.  Remember to separately advise the Expert Witness as to the password for any documents provided electronically.
  • Identify the key legal aspects of the case from your client’s perspective.
  • Identify issues that need to be addressed in the Expert Witness’s report/advice.
  • Put the duty on the expert to inform you whether they feel they are the right person for the task or not
  • List duties of an Expert Witness – with emphasis on not being an advocate.
  • Identify a list of issues to be addressed in the report
  • Timetable – lay out key dates and framework with court submissions date for report so expert can manage their time.
  • Confirm payment terms.

Why not use our template initial letter of instruction?
Letters of Instruction

Further letters of Instruction

Further letters of instruction may be necessary as the case develops relating to:

  • Experts’ Meeting and Joint Statement
  • Supplemental reports
  • Additional evidence to consider
  • Consultation with Counsel
  • Details about the trial, including date and how long it is expected to last
  • Whether the Expert Witness will be required to give concurrent evidence (Hot-Tubbing)
  • Explain that the Expert Witness has the right to ask for directions from court in civil matters
  • Questions on Expert Witness’s reports in civil matters– explain that the other party has the right to ask questions about the report up until 28 days after submission

Common pitfalls

  • Make sure that the summary of the case in the instruction letter is clear and fair.
  • Provide all the relevant documents and evidence at the beginning.
  • Identify clear questions for the Expert Witness to answer.
  • Constructive criticism leads to great reports – but never try to tell the Expert Witness what to put in their report.  It is legitimate to ask an expert witness to clarify their report, it is not legitimate to seek to influence the content of the report.