Key takeaways
- An IME physician examines the plaintiff; an expert witness usually opines from the records.
- IMEs are governed by rule and statute, including notice and scope limits.
- The same physician can do both, but the roles carry different discovery obligations.
Two different roles
An IME (independent medical examination) is a one-time examination of a claimant, usually arranged by the defense or an insurer under court rule or policy terms, producing a report on diagnosis, causation, and functional status. A retained expert witness is engaged by one party to review the full record, form litigation opinions, and testify.
The IME physician's mandate is nominally neutral evaluation of the person examined; the retained expert's mandate is rigorous analysis of the case within their specialty. In practice, IME reports become evidence and IME doctors become witnesses, so the distinction blurs, and both roles demand credible, defensible physicians.
When you need which
Defense counsel typically needs both: an IME to evaluate the claimant directly, and retained experts for standard-of-care or causation opinions beyond the examination. Plaintiff counsel confronts IMEs by retaining experts to rebut the report's methodology and conclusions, a common engagement on Retain.
Practical differences
IMEs are constrained by examination rules (scope, recording, who may attend) that vary by jurisdiction; retained expert work is governed by discovery rules and disclosure deadlines. Fees differ too: IMEs are usually flat-fee; retained work is hourly. Physicians on Retain indicate whether they perform examinations, record-only reviews, or both.
About the author
Sales and Marketing Leader, Retain
Michael has spent more than 25 years leading sales and marketing teams in pharmaceuticals, medical devices, and healthcare diagnostics, including 10 product launches and P&L responsibility up to $150M. He writes about how attorneys and physicians actually work together on expert engagements.
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