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

As the US reflects on 250 years of independence, patent lawyers say innovation is reshaping old hiring priorities, with firms seeking broader IP expertise over specialisation
The Nokia v Acer ruling in the UK suggests arbitration is moving from the sidelines towards the mainstream of global FRAND disputes - and could reshape forum strategy in the process
The Life Sciences Awards is thrilled to present the shortlist for the 2026 Americas Awards
From Türkiye to Poland and Nigeria, firms with deep local roots continue to dominate the top tier, proving that market expertise can outweigh international scale in many CEE, Middle Eastern and African jurisdictions
Former Hoyng Rokh partner Simon Dack takes a leading PMAC role as busy firms continue to jostle for position
Franck Fougere, founder and managing partner of Ananda IP in Thailand, describes how the firm has developed a reputation for patent work and why he believes IP practice is set to change
After two decades at Kass International, Geetha Kandiah discusses the lessons that shaped her career, building an inclusive regional firm, and AI opportunities
Manisha Singh of LexOrbis discusses the need for commercial alignment with clients and why IP lawyers need to have curiosity at their core
As firms expand into integrated IP services, recent hires show the model's appeal – but high-profile departures reveal how quickly questions of depth and durability can emerge
In-house counsel say private practice firms either aren’t conveying sustainability messaging or simply ‘don’t care’, but a mindful approach to the topic could swing pitches
Gift this article