Expert witnesses in patent litigation around the world

Managing IP is part of Legal Benchmarking Limited, 1-2 Paris Gardens, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement

Expert witnesses in patent litigation around the world

geek.jpg

Expert witnesses can be decisive in the outcome of patent cases, but rules on their use vary widely. We invited correspondents in Germany, Japan, the UK and US to discuss procedures and practical tips

geek.jpg

With so much IP litigation today being international, and involving an element of forum-shopping, parties have to weigh up many considerations when deciding where and when to bring an action, or how to defend it.

Some of these questions are purely legal: What rights do we have? Do we have standing? What actions are permitted in a particular jurisdiction? But many questions are also strategic: How long will a case take? What will it cost? How will it be decided? What evidence can be brought? Often, these strategic questions are decisive for the outcome of the dispute.

In patent litigation in particular, the role played by expert witnesses can be vital, especially in cases where the technology is complex and judgements about validity and infringement can be finely balanced. And yet the rules on the use of experts vary greatly between different jurisdictions.

Germany, Japan, UK and US compared

In a special feature published this month, we invited correspondents in Germany, Japan, the UK and US to describe how expert witnesses are used in litigation in those four jurisdictions, and also how parties can make the most of expert witnesses.

In Germany, courts recognise both court-appointed experts and party experts – though in practice they are only used in a tiny number of cases. Courts place tight restrictions on the use of court-appointed experts, while party experts may be of limited value and may even do more harm than good.

Japan also has different types of experts, and the role of judicial research officials and technical advisers is especially important in patent cases. Technical advisers in particular are now an accepted and well understood part of litigation in the country.

In the UK courts, experts play a vital role and can even be instrumental in the outcome of a case. Selecting the right expert and carefully instructing them is therefore a crucial part of litigation strategy. What is required of experts has been elucidated in a number of cases over the years and it is also important to consider personality issues: how credible will your expert be before a judge, particularly in cross-examination?

Similarly, in US litigation both consulting and testifying experts provide the court with invaluable assistance that may be case determinative (and a strong expert report may lead to pre-trial settlement). The standards expected of experts have been clarified in federal rules and case law and, as in the UK, the ability to select and prepare your expert is a key skill for litigators.

Comments welcome

We selected these four countries as they are among the most important in patent litigation globally; we may cover other countries in future issues if readers are interested, so please do let us know via the comments.

more from across site and SHARED ros bottom lb

More from across our site

K&L Gates and Baker Botts have recruited leading patent practitioners from Wende IP and EIP, respectively, as they seek to strengthen European patent litigation capabilities
The departure of a large chunk of Spruson & Ferguson's legacy leadership could have destabilised the firm, but it's fighting back with strategic hires and promotions
By accepting a relatively small sample of infringing content to grant worldwide relief, a UK court has adopted a pragmatic approach that could reduce the time and expense involved in huge enforcement actions
This year’s IP STARS Americas rankings reveal that firms are expanding their capabilities, particularly in trade secrets and life sciences
Law firms’ expanding IP capabilities are driving broader industry recognition across a wider range of practice areas
As specialist boutiques challenge traditional firm models, major disputes involving Disney, Ericsson, Siemens and Dolby highlight the firms winning work before the UPC
The firm has added two leading damages specialists as it expands beyond technical analysis and deepens its role in the economics of IP litigation
Josh Seidenfeld, partner at DLA Piper, outlines the emerging legal trends that drive the future of life sciences innovation and how stakeholders can prepare for the future
South Korea's One Law Partners is combining with boutique firm Minwho Law Group to leverage global expansion of K-content and build a broader offering spanning IP, tech and regulatory advisory work
Russell Kennedy's Gina Tresidder on juggling matters, delivering hard truths, and why IP ownership is rarely as simple as people think
Gift this article